My website has translations, and I want to translate my error pages. But I translate my pages with a dynamic route (/app/[locale]) and not-found.tsx must be at the root (app/not-found.tsx). I don't use any libraries for my internationalisation.

What I tried: I created a custom error page in my /app/[locale]/ folder at /app/[locale]/404/page.tsx.

Then, my middleware sends all the non-valid urls to /[locale]/404 with the right locale.

The problem is: I can't find a way to fire a 404 status code.

I tried to set the status code from the middleware, but then I can't redirect to my custom error page. (NextResponse.redirect doesn't support status codes).

I tried using use notFound() in 404/page.tsx, but then app/not-found.tsx is rendered and not 404/page.tsx.