Do I need a specific license to install german vehicles and clothing on my server?
What makes you think that? As long as you keep within FiveM’s ToS (see here) you can install whatever vehicles and other assets onto the server.
I mean if I need a license to set up a German RP server with German vehicles and clothing
For custom clothing u need an key from keymaster…
You need an subscription on patreon to stream custom clothing on your server.
Like the Element Club Argentum
Greetings