diff --git a/packages/code-du-travail-frontend/cypress/integration/conventions-collectives.spec.ts b/packages/code-du-travail-frontend/cypress/integration/conventions-collectives.spec.ts
index 5dfb8f19c8..763dd14949 100644
--- a/packages/code-du-travail-frontend/cypress/integration/conventions-collectives.spec.ts
+++ b/packages/code-du-travail-frontend/cypress/integration/conventions-collectives.spec.ts
@@ -16,4 +16,20 @@ describe("Conventions collectives", () => {
       "/convention-collective/2941-aide-accompagnement-soins-et-services-a-domicile-bad"
     );
   });
+  it("je suis redirigé vers la cc si je mets seulement l'idcc dans l'url", () => {
+    cy.visit("/convention-collective/0029");
+    cy.url().should(
+      "include",
+      "/convention-collective/29-hospitalisation-privee-etablissements-prives-dhospitalisation-de-soins-d"
+    );
+  });
+  it("je vois une 404 si l'iddc n'existe pas", () => {
+    cy.request({
+      failOnStatusCode: false,
+      method: "GET",
+      url: "/convention-collective/1234",
+    }).then((response) => {
+      expect(response.status).to.equal(404);
+    });
+  });
 });
diff --git a/packages/code-du-travail-frontend/pages/convention-collective/[slug].tsx b/packages/code-du-travail-frontend/pages/convention-collective/[slug].tsx
index 13c691c513..3580057458 100644
--- a/packages/code-du-travail-frontend/pages/convention-collective/[slug].tsx
+++ b/packages/code-du-travail-frontend/pages/convention-collective/[slug].tsx
@@ -11,6 +11,7 @@ import Convention from "../../src/conventions/Convention";
 import { Layout } from "../../src/layout/Layout";
 import { handleError } from "../../src/lib/fetch-error";
 import { SITE_URL } from "../../src/config";
+import { apiIdcc } from "../../src/conventions/Search/api/agreement.service";
 
 interface Props {
   convention;
@@ -80,12 +81,20 @@ function ConventionCollective(props: Props): JSX.Element {
   );
 }
 
+const IDCC_ONLY = /^\d{2,4}$/;
 export const getServerSideProps = async ({ query }) => {
-  const responseContainer = await fetch(`${SITE_URL}/api/agreements/${query.slug}`);
-  if (!responseContainer.ok) {
-    return handleError(responseContainer);
+  if (IDCC_ONLY.test(query.slug)) {
+    const conventions = await apiIdcc(query.slug.padStart(4, "0"));
+    if (!conventions.length) {
+      return { notFound: true };
+    }
+    return { redirect: { destination: conventions[0].slug, permanent: true } };
   }
-  const convention = await responseContainer.json();
+  const res = await fetch(`${SITE_URL}/api/agreements/${query.slug}`);
+  if (!res.ok) {
+    return handleError(res);
+  }
+  const convention = await res.json();
   return { props: { convention } };
 };
 
diff --git a/packages/code-du-travail-frontend/src/conventions/Search/api/agreement.service.ts b/packages/code-du-travail-frontend/src/conventions/Search/api/agreement.service.ts
index 146ee64f7f..cf85bb6175 100644
--- a/packages/code-du-travail-frontend/src/conventions/Search/api/agreement.service.ts
+++ b/packages/code-du-travail-frontend/src/conventions/Search/api/agreement.service.ts
@@ -32,4 +32,4 @@ const apiIdcc = function createFetcher(query: string): Promise<Agreement[]> {
 
 const searchAgreement = debounce(apiIdcc, 300);
 
-export { searchAgreement };
+export { searchAgreement, apiIdcc };