diff --git a/src/frontend/apps/e2e/__tests__/app-impress/doc-member-create.spec.ts b/src/frontend/apps/e2e/__tests__/app-impress/doc-member-create.spec.ts
index fbb0db78..a4445ff9 100644
--- a/src/frontend/apps/e2e/__tests__/app-impress/doc-member-create.spec.ts
+++ b/src/frontend/apps/e2e/__tests__/app-impress/doc-member-create.spec.ts
@@ -111,6 +111,9 @@ test.describe('Document create member', () => {
     await expect(page.getByText(`Invitation sent to ${email}`)).toBeVisible();
     const responseCreateInvitation = await responsePromiseCreateInvitation;
     expect(responseCreateInvitation.ok()).toBeTruthy();
+    expect(
+      responseCreateInvitation.request().headers()['content-language'],
+    ).toBe('en-us');
 
     // Check user added
     await expect(
@@ -209,4 +212,44 @@ test.describe('Document create member', () => {
       await responsePromiseCreateInvitationFail;
     expect(responseCreateInvitationFail.ok()).toBeFalsy();
   });
+
+  test('The invitation endpoint get the language of the website', async ({
+    page,
+    browserName,
+  }) => {
+    await createDoc(page, 'user-invitation', browserName, 1);
+
+    const header = page.locator('header').first();
+    await header.getByRole('combobox').getByText('EN').click();
+    await header.getByRole('option', { name: 'FR' }).click();
+
+    await page.getByRole('button', { name: 'Partager' }).click();
+
+    const inputSearch = page.getByLabel(
+      /Trouver un membre à ajouter au document/,
+    );
+
+    const email = randomName('test@test.fr', browserName, 1)[0];
+    await inputSearch.fill(email);
+    await page.getByRole('option', { name: email }).click();
+
+    // Choose a role
+    await page.getByRole('combobox', { name: /Choisissez un rôle/ }).click();
+    await page.getByRole('option', { name: 'Administrateur' }).click();
+
+    const responsePromiseCreateInvitation = page.waitForResponse(
+      (response) =>
+        response.url().includes('/invitations/') && response.status() === 201,
+    );
+
+    await page.getByRole('button', { name: 'Valider' }).click();
+
+    // Check invitation sent
+    await expect(page.getByText(`Invitation envoyée à ${email}`)).toBeVisible();
+    const responseCreateInvitation = await responsePromiseCreateInvitation;
+    expect(responseCreateInvitation.ok()).toBeTruthy();
+    expect(
+      responseCreateInvitation.request().headers()['content-language'],
+    ).toBe('fr-fr');
+  });
 });
diff --git a/src/frontend/apps/impress/src/features/docs/members/members-add/api/useCreateDocInvitation.tsx b/src/frontend/apps/impress/src/features/docs/members/members-add/api/useCreateDocInvitation.tsx
index cc26f4e3..c443a112 100644
--- a/src/frontend/apps/impress/src/features/docs/members/members-add/api/useCreateDocInvitation.tsx
+++ b/src/frontend/apps/impress/src/features/docs/members/members-add/api/useCreateDocInvitation.tsx
@@ -3,6 +3,7 @@ import { useMutation } from '@tanstack/react-query';
 import { APIError, errorCauses, fetchAPI } from '@/api';
 import { User } from '@/core/auth';
 import { Doc, Role } from '@/features/docs/doc-management';
+import { ContentLanguage } from '@/i18n/types';
 
 import { DocInvitation, OptionType } from '../types';
 
@@ -10,15 +11,20 @@ interface CreateDocInvitationParams {
   email: User['email'];
   role: Role;
   docId: Doc['id'];
+  contentLanguage: ContentLanguage;
 }
 
 export const createDocInvitation = async ({
   email,
   role,
   docId,
+  contentLanguage,
 }: CreateDocInvitationParams): Promise<DocInvitation> => {
   const response = await fetchAPI(`documents/${docId}/invitations/`, {
     method: 'POST',
+    headers: {
+      'Content-Language': contentLanguage,
+    },
     body: JSON.stringify({
       email,
       role,
diff --git a/src/frontend/apps/impress/src/features/docs/members/members-add/components/AddMembers.tsx b/src/frontend/apps/impress/src/features/docs/members/members-add/components/AddMembers.tsx
index d33a5082..51d183c1 100644
--- a/src/frontend/apps/impress/src/features/docs/members/members-add/components/AddMembers.tsx
+++ b/src/frontend/apps/impress/src/features/docs/members/members-add/components/AddMembers.tsx
@@ -9,6 +9,7 @@ import { useTranslation } from 'react-i18next';
 import { APIError } from '@/api';
 import { Box, Card, IconBG } from '@/components';
 import { Doc, Role } from '@/features/docs/doc-management';
+import { useLanguage } from '@/i18n/hooks/useLanguage';
 
 import { useCreateDocAccess, useCreateInvitation } from '../api';
 import {
@@ -33,6 +34,7 @@ interface ModalAddMembersProps {
 }
 
 export const AddMembers = ({ currentRole, doc }: ModalAddMembersProps) => {
+  const { contentLanguage } = useLanguage();
   const { t } = useTranslation();
   const [selectedUsers, setSelectedUsers] = useState<OptionsSelect>([]);
   const [selectedRole, setSelectedRole] = useState<Role>();
@@ -51,6 +53,7 @@ export const AddMembers = ({ currentRole, doc }: ModalAddMembersProps) => {
             email: selectedUser.value.email,
             role: selectedRole,
             docId: doc.id,
+            contentLanguage,
           });
           break;
 
diff --git a/src/frontend/apps/impress/src/i18n/hooks/useLanguage.tsx b/src/frontend/apps/impress/src/i18n/hooks/useLanguage.tsx
new file mode 100644
index 00000000..4879bda8
--- /dev/null
+++ b/src/frontend/apps/impress/src/i18n/hooks/useLanguage.tsx
@@ -0,0 +1,15 @@
+import { useTranslation } from 'react-i18next';
+
+import { ContentLanguage } from '../types';
+
+export const useLanguage = (): {
+  language: string;
+  contentLanguage: ContentLanguage;
+} => {
+  const { i18n } = useTranslation();
+
+  return {
+    language: i18n.language,
+    contentLanguage: i18n.language === 'fr' ? 'fr-fr' : 'en-us',
+  };
+};
diff --git a/src/frontend/apps/impress/src/i18n/types.ts b/src/frontend/apps/impress/src/i18n/types.ts
new file mode 100644
index 00000000..d9b0064a
--- /dev/null
+++ b/src/frontend/apps/impress/src/i18n/types.ts
@@ -0,0 +1,2 @@
+// See: https://github.com/numerique-gouv/impress/blob/ac58341984c99c10ebfac7f8bbe1e8756c48e4d4/src/backend/impress/settings.py#L156-L161
+export type ContentLanguage = 'en-us' | 'fr-fr';