frontend/src/components/MitreMatrixModal.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState } from 'react';
+import { useTranslation } from 'react-i18next';
 import { LoadingState } from './LoadingState';
 import { ErrorState } from './ErrorState';
 import { extractApiError } from '@/api/client';
@@ -41,6 +42,7 @@ export function MitreMatrixModal({
   onApply,
   onCancel,
 }: MitreMatrixModalProps): JSX.Element | null {
+  const { t } = useTranslation();
   const { data: matrix, isLoading, isError, error } = useMitreMatrix(isOpen);
 
   const [selectedTechMap, setSelectedTechMap] = useState<Map<string, { id: string; name: string }>>(
@@ -177,24 +179,24 @@ export function MitreMatrixModal({
         {/* Header */}
         <div className="flex items-center justify-between px-xl py-md border-b border-hairline flex-shrink-0">
           <h2 id="matrix-modal-title" className="text-[18px] font-medium text-ink">
-            MITRE ATT&amp;CK Matrix
+            {t('mitre.matrix.title')}
           </h2>
           <input
             ref={searchInputRef}
             type="text"
-            placeholder="Filter techniques…"
+            placeholder={t('mitre.matrix.filter')}
             value={search}
             onChange={(e) => setSearch(e.target.value)}
             className="text-input w-56 h-9 text-[14px]"
-            aria-label="Filter techniques"
+            aria-label={t('mitre.matrix.filter')}
           />
         </div>
 
         {/* Body — overflow-y-auto, NO overflow-x */}
         <div className="flex-1 overflow-y-auto overflow-x-hidden px-md py-md">
-          {isLoading && <LoadingState label="Loading MITRE matrix…" />}
+          {isLoading && <LoadingState label={t('mitre.matrix.loading')} />}
           {isError && (
-            <ErrorState message={extractApiError(error, 'Could not load MITRE matrix')} />
+            <ErrorState message={extractApiError(error, t('mitre.matrix.error'))} />
           )}
           {!isLoading && !isError && matrix && (
             <div
@@ -340,7 +342,7 @@ export function MitreMatrixModal({
         {/* Footer */}
         <div className="flex items-center justify-end gap-md px-xl py-md border-t border-hairline flex-shrink-0">
           <button type="button" className="btn-outline-ink" onClick={onCancel}>
-            Cancel
+            {t('mitre.matrix.close')}
           </button>
           <button
             type="button"
@@ -349,8 +351,8 @@ export function MitreMatrixModal({
             disabled={isLoading || isError || (totalSelected === 0 && !hasInitial)}
           >
             {totalSelected === 0
-              ? 'Clear all'
+              ? t('mitre.matrix.clearAll')
-              : `Apply ${totalSelected} item${totalSelected !== 1 ? 's' : ''}`}
+              : t(totalSelected === 1 ? 'mitre.matrix.applyItem_one' : 'mitre.matrix.applyItem_other', { count: totalSelected })}
           </button>
         </div>
       </div>

frontend/src/components/MitreTechniquePicker.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState, type KeyboardEvent } from 'react';
+import { useTranslation } from 'react-i18next';
 import { extractApiError } from '@/api/client';
 import type { MitreTechnique } from '@/api/types';
 import { useMitreSearch } from '@/hooks/useMitre';
@@ -14,6 +15,7 @@ export function MitreTechniquePicker({
   onSelect,
   disabled = false,
 }: MitreTechniquePickerProps): JSX.Element {
+  const { t } = useTranslation();
   const [inputValue, setInputValue] = useState('');
   const [query, setQuery] = useState('');
   const [open, setOpen] = useState(false);
@@ -95,31 +97,31 @@ export function MitreTechniquePicker({
         aria-expanded={open}
         aria-controls={listboxId}
         aria-activedescendant={activeIndex >= 0 ? `mitre-option-${activeIndex}` : undefined}
-        aria-label="Search MITRE technique"
+        aria-label={t('mitre.field.search')}
         className="text-input"
         value={inputValue}
         onChange={(e) => handleInputChange(e.target.value)}
         onFocus={() => setOpen(true)}
         onKeyDown={handleKeyDown}
         disabled={disabled}
-        placeholder="Search by ID or name (e.g. T1059)"
+        placeholder={t('mitre.field.search')}
         autoComplete="off"
       />
 
       {open && (
         <div className="absolute z-20 w-full mt-xxs bg-paper border border-steel rounded-none overflow-hidden">
           {isFetching && (
-            <div className="px-md py-sm text-[14px] text-graphite">Searching…</div>
+            <div className="px-md py-sm text-[14px] text-graphite">{t('state.loading')}</div>
           )}
 
           {isError && !isFetching && (
             <div className="px-md py-sm text-[14px] text-bloom-deep" role="alert">
-              {extractApiError(error, 'MITRE search unavailable')}
+              {extractApiError(error, t('mitre.matrix.error'))}
             </div>
           )}
 
           {!isFetching && !isError && items.length === 0 && query.trim().length > 0 && (
-            <div className="px-md py-sm text-[14px] text-graphite">No results</div>
+            <div className="px-md py-sm text-[14px] text-graphite">{t('state.empty.default')}</div>
           )}
 
           {!isFetching && items.length > 0 && (

frontend/src/components/MitreTechniqueTag.tsx

@@ -1,3 +1,4 @@
+import { useTranslation } from 'react-i18next';
 import type { MitreTechnique, MitreTacticRef } from '@/api/types';
 
 interface TechniqueTagProps {
@@ -18,6 +19,7 @@ export function MitreTechniqueTag({
   onRemove,
   disabled = false,
 }: TechniqueTagProps): JSX.Element {
+  const { t } = useTranslation();
   return (
     <span
       data-testid="mitre-technique-tag"
@@ -28,7 +30,7 @@ export function MitreTechniqueTag({
       {!disabled && (
         <button
           type="button"
-          aria-label={`Remove ${technique.id}`}
+          aria-label={`${t('mitre.tag.remove')} ${technique.id}`}
           onClick={onRemove}
           className="text-primary-deep opacity-60 hover:opacity-100 leading-none"
         >
@@ -45,6 +47,7 @@ export function MitreTacticTag({
   onRemove,
   disabled = false,
 }: TacticTagProps): JSX.Element {
+  const { t } = useTranslation();
   return (
     <span
       data-testid="mitre-tactic-tag"
@@ -55,7 +58,7 @@ export function MitreTacticTag({
       {!disabled && (
         <button
           type="button"
-          aria-label={`Remove ${tactic.id}`}
+          aria-label={`${t('mitre.tag.remove')} ${tactic.id}`}
           onClick={onRemove}
           className="text-white opacity-60 hover:opacity-100 leading-none"
         >

frontend/src/components/MitreTechniquesField.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react';
 import { Grid2x2 } from 'lucide-react';
+import { useTranslation } from 'react-i18next';
 import { extractApiError } from '@/api/client';
 import type { MitreTechnique, MitreTacticRef } from '@/api/types';
 import { useUpdateSimulation } from '@/hooks/useSimulations';
@@ -24,6 +25,7 @@ export function MitreTechniquesField({
   engagementId,
   disabled = false,
 }: MitreTechniquesFieldProps): JSX.Element {
+  const { t } = useTranslation();
   const [showMatrix, setShowMatrix] = useState(false);
   const [showPicker, setShowPicker] = useState(false);
 
@@ -33,34 +35,34 @@ export function MitreTechniquesField({
   const save = async (techniques: MitreTechnique[], nextTactics: MitreTacticRef[]) => {
     try {
       await updateMutation.mutateAsync({
-        technique_ids: techniques.map((t) => t.id),
+        technique_ids: techniques.map((tech) => tech.id),
-        tactic_ids: nextTactics.map((t) => t.id),
+        tactic_ids: nextTactics.map((tac) => tac.id),
       });
-      push('Techniques updated', 'success');
+      push(t('mitre.field.savedToast'), 'success');
     } catch (err) {
-      push(extractApiError(err, 'Could not update techniques'), 'error');
+      push(extractApiError(err, t('mitre.field.errorToast')), 'error');
     }
   };
 
   const handleRemoveTechnique = (id: string) => {
-    void save(value.filter((t) => t.id !== id), tactics);
+    void save(value.filter((tech) => tech.id !== id), tactics);
   };
 
   const handleRemoveTactic = (id: string) => {
-    void save(value, tactics.filter((t) => t.id !== id));
+    void save(value, tactics.filter((tac) => tac.id !== id));
   };
 
   const handleSelect = (technique: MitreTechnique) => {
-    if (value.some((t) => t.id === technique.id)) return;
+    if (value.some((tech) => tech.id === technique.id)) return;
     void save([...value, technique], tactics);
     setShowPicker(false);
   };
 
   const handleMatrixApply = ({ techniques, tactics: newTactics }: MatrixSelection) => {
     setShowMatrix(false);
-    const merged = techniques.map((s) => {
+    const merged = techniques.map((sel) => {
-      const existing = value.find((v) => v.id === s.id);
+      const existing = value.find((v) => v.id === sel.id);
-      return existing ?? s;
+      return existing ?? sel;
     });
     void save(merged, newTactics);
   };
@@ -72,22 +74,22 @@ export function MitreTechniquesField({
     <div className="flex flex-col gap-sm">
       {/* Chips area */}
       {isEmpty ? (
-        <p className="text-[13px] text-graphite">No techniques selected</p>
+        <p className="text-[13px] text-graphite">{t('mitre.field.empty')}</p>
       ) : (
         <div className="flex flex-wrap gap-xs" data-testid="techniques-tag-list">
-          {tactics.map((t) => (
+          {tactics.map((tac) => (
             <MitreTacticTag
-              key={t.id}
+              key={tac.id}
-              tactic={t}
+              tactic={tac}
-              onRemove={() => handleRemoveTactic(t.id)}
+              onRemove={() => handleRemoveTactic(tac.id)}
               disabled={disabled || isPending}
             />
           ))}
-          {value.map((t) => (
+          {value.map((tech) => (
             <MitreTechniqueTag
-              key={t.id}
+              key={tech.id}
-              technique={t}
+              technique={tech}
-              onRemove={() => handleRemoveTechnique(t.id)}
+              onRemove={() => handleRemoveTechnique(tech.id)}
               disabled={disabled || isPending}
             />
           ))}
@@ -107,20 +109,20 @@ export function MitreTechniquesField({
                 onClick={() => setShowPicker(true)}
                 disabled={isPending}
               >
-                Search technique (e.g. T1059)…
+                {t('mitre.field.search')}
               </button>
             )}
           </div>
           <button
             type="button"
-            aria-label="Open MITRE matrix"
+            aria-label={t('mitre.field.openMatrix')}
             onClick={() => { setShowPicker(false); setShowMatrix(true); }}
             disabled={isPending}
             className="flex-shrink-0 flex items-center justify-center w-9 h-9 rounded-none border border-steel text-graphite hover:text-ink hover:border-ink"
           >
             <Grid2x2 size={16} />
           </button>
-          {isPending && <span className="text-[12px] text-graphite">Saving…</span>}
+          {isPending && <span className="text-[12px] text-graphite">{t('common.saving')}</span>}
         </div>
       )}
 

frontend/tests/MitreMatrixModal.test.tsx

@@ -124,7 +124,7 @@ describe('MitreMatrixModal', () => {
     );
     await user.click(t1078Btn!);
 
-    await user.click(screen.getByRole('button', { name: /Apply/i }));
+    await user.click(screen.getByRole('button', { name: /Appliquer/i }));
 
     expect(onApply).toHaveBeenCalledWith(
       expect.objectContaining({
@@ -148,7 +148,7 @@ describe('MitreMatrixModal', () => {
       />,
     );
 
-    await user.click(screen.getByRole('button', { name: /Cancel/i }));
+    await user.click(screen.getByRole('button', { name: /Fermer/i }));
 
     expect(onCancel).toHaveBeenCalled();
     expect(onApply).not.toHaveBeenCalled();
@@ -202,7 +202,7 @@ describe('MitreMatrixModal', () => {
 
     await waitFor(() => screen.getByText('T1078'));
 
-    const searchInput = screen.getByPlaceholderText(/Filter techniques/i);
+    const searchInput = screen.getByPlaceholderText(/Filtrer/i);
     await user.type(searchInput, 'T1059');
 
     expect(screen.queryByText('T1078')).toBeNull();
@@ -242,7 +242,7 @@ describe('MitreMatrixModal', () => {
     );
 
     await waitFor(() => {
-      expect(screen.getByRole('button', { name: /Apply 1 item/i })).toBeInTheDocument();
+      expect(screen.getByRole('button', { name: /Appliquer \(1 élément\)/i })).toBeInTheDocument();
     });
   });
 
@@ -259,11 +259,11 @@ describe('MitreMatrixModal', () => {
 
     await waitFor(() => screen.getByText('T1078'));
 
-    const applyBtn = screen.getByRole('button', { name: /Clear all/i });
+    const applyBtn = screen.getByRole('button', { name: /Tout effacer/i });
     expect(applyBtn).toBeDisabled();
   });
 
-  it('Apply button shows "Clear all" and is enabled when initial selection is deselected', async () => {
+  it('Apply button shows "Tout effacer" and is enabled when initial selection is deselected', async () => {
     const onApply = vi.fn();
     const user = userEvent.setup();
 
@@ -284,7 +284,7 @@ describe('MitreMatrixModal', () => {
     );
     await user.click(t1078Btn!);
 
-    const applyBtn = screen.getByRole('button', { name: /Clear all/i });
+    const applyBtn = screen.getByRole('button', { name: /Tout effacer/i });
     expect(applyBtn).not.toBeDisabled();
     await user.click(applyBtn);
     expect(onApply).toHaveBeenCalledWith(

frontend/tests/MitreTechniquePicker.test.tsx

@@ -30,7 +30,7 @@ describe('MitreTechniquePicker', () => {
     vi.useRealTimers();
     renderWithProviders(<MitreTechniquePicker onSelect={vi.fn()} />);
     expect(screen.getByRole('combobox')).toBeInTheDocument();
-    expect(screen.getByPlaceholderText(/Search by ID or name/i)).toBeInTheDocument();
+    expect(screen.getByPlaceholderText(/Rechercher une technique/i)).toBeInTheDocument();
   });
 
   it('is disabled when disabled prop is true', () => {

frontend/tests/MitreTechniqueTag.test.tsx

@@ -23,7 +23,7 @@ describe('MitreTechniqueTag', () => {
     renderWithProviders(
       <MitreTechniqueTag technique={TECHNIQUE} onRemove={vi.fn()} />,
     );
-    expect(screen.getByRole('button', { name: /Remove T1059/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /Retirer T1059/i })).toBeInTheDocument();
   });
 
   it('clicking × calls onRemove', async () => {
@@ -32,7 +32,7 @@ describe('MitreTechniqueTag', () => {
     renderWithProviders(
       <MitreTechniqueTag technique={TECHNIQUE} onRemove={onRemove} />,
     );
-    await user.click(screen.getByRole('button', { name: /Remove T1059/i }));
+    await user.click(screen.getByRole('button', { name: /Retirer T1059/i }));
     expect(onRemove).toHaveBeenCalledOnce();
   });
 
@@ -40,7 +40,7 @@ describe('MitreTechniqueTag', () => {
     renderWithProviders(
       <MitreTechniqueTag technique={TECHNIQUE} onRemove={vi.fn()} disabled />,
     );
-    expect(screen.queryByRole('button', { name: /Remove/i })).toBeNull();
+    expect(screen.queryByRole('button', { name: /Retirer/i })).toBeNull();
   });
 });
 
@@ -57,7 +57,7 @@ describe('MitreTacticTag', () => {
     renderWithProviders(
       <MitreTacticTag tactic={TACTIC} onRemove={vi.fn()} />,
     );
-    expect(screen.getByRole('button', { name: /Remove TA0007/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /Retirer TA0007/i })).toBeInTheDocument();
   });
 
   it('clicking × calls onRemove', async () => {
@@ -66,7 +66,7 @@ describe('MitreTacticTag', () => {
     renderWithProviders(
       <MitreTacticTag tactic={TACTIC} onRemove={onRemove} />,
     );
-    await user.click(screen.getByRole('button', { name: /Remove TA0007/i }));
+    await user.click(screen.getByRole('button', { name: /Retirer TA0007/i }));
     expect(onRemove).toHaveBeenCalledOnce();
   });
 
@@ -74,6 +74,6 @@ describe('MitreTacticTag', () => {
     renderWithProviders(
       <MitreTacticTag tactic={TACTIC} onRemove={vi.fn()} disabled />,
     );
-    expect(screen.queryByRole('button', { name: /Remove/i })).toBeNull();
+    expect(screen.queryByRole('button', { name: /Retirer/i })).toBeNull();
   });
 });

frontend/tests/MitreTechniquesField.test.tsx

@@ -48,7 +48,7 @@ describe('MitreTechniquesField', () => {
     renderWithProviders(
       <MitreTechniquesField value={[]} tactics={[]} simulationId={7} engagementId={42} />,
     );
-    expect(screen.getByText(/No techniques selected/i)).toBeInTheDocument();
+    expect(screen.getByText(/Aucune technique associée/i)).toBeInTheDocument();
   });
 
   it('renders technique tags for each technique', () => {
@@ -72,16 +72,16 @@ describe('MitreTechniquesField', () => {
     renderWithProviders(
       <MitreTechniquesField value={[]} tactics={[]} simulationId={7} engagementId={42} />,
     );
-    expect(screen.getByRole('button', { name: /Open MITRE matrix/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /Ouvrir la matrice/i })).toBeInTheDocument();
     // The search placeholder button
-    expect(screen.getByRole('button', { name: /Search technique/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /Rechercher une technique/i })).toBeInTheDocument();
   });
 
   it('hides input row when disabled', () => {
     renderWithProviders(
       <MitreTechniquesField value={[T1059]} tactics={[]} simulationId={7} engagementId={42} disabled />,
     );
-    expect(screen.queryByRole('button', { name: /Open MITRE matrix/i })).toBeNull();
+    expect(screen.queryByRole('button', { name: /Ouvrir la matrice/i })).toBeNull();
   });
 
   it('× button on technique tag calls PATCH with technique removed', async () => {
@@ -94,7 +94,7 @@ describe('MitreTechniquesField', () => {
       <MitreTechniquesField value={[T1059, T1078]} tactics={[]} simulationId={7} engagementId={42} />,
     );
 
-    const removeBtn = screen.getByRole('button', { name: /Remove T1059/i });
+    const removeBtn = screen.getByRole('button', { name: /Retirer T1059/i });
     await user.click(removeBtn);
 
     await waitFor(() => {
@@ -115,7 +115,7 @@ describe('MitreTechniquesField', () => {
       <MitreTechniquesField value={[T1059]} tactics={[TA0007]} simulationId={7} engagementId={42} />,
     );
 
-    const removeBtn = screen.getByRole('button', { name: /Remove TA0007/i });
+    const removeBtn = screen.getByRole('button', { name: /Retirer TA0007/i });
     await user.click(removeBtn);
 
     await waitFor(() => {
@@ -131,7 +131,7 @@ describe('MitreTechniquesField', () => {
     renderWithProviders(
       <MitreTechniquesField value={[]} tactics={[]} simulationId={7} engagementId={42} />,
     );
-    await user.click(screen.getByRole('button', { name: /Search technique/i }));
+    await user.click(screen.getByRole('button', { name: /Rechercher une technique/i }));
     expect(screen.getByRole('combobox')).toBeInTheDocument();
   });
 
@@ -142,7 +142,7 @@ describe('MitreTechniquesField', () => {
       <MitreTechniquesField value={[T1059]} tactics={[]} simulationId={7} engagementId={42} />,
     );
 
-    await user.click(screen.getByRole('button', { name: /Search technique/i }));
+    await user.click(screen.getByRole('button', { name: /Rechercher une technique/i }));
     const combobox = screen.getByRole('combobox');
 
     await user.type(combobox, 'T1059');
@@ -161,7 +161,7 @@ describe('MitreTechniquesField', () => {
     renderWithProviders(
       <MitreTechniquesField value={[]} tactics={[]} simulationId={7} engagementId={42} />,
     );
-    await user.click(screen.getByRole('button', { name: /Open MITRE matrix/i }));
+    await user.click(screen.getByRole('button', { name: /Ouvrir la matrice/i }));
     expect(screen.getByRole('dialog')).toBeInTheDocument();
   });
 });