I know what it is! It's an Indy/Formula 1 promotional kart.
You can't do better than a rolling, driveable mini-car billboard that's advertising "GAFGLAS MEMBRANES".
I don't even know what that is, honestly and I don't want to know...
I'd crawl all over it high and low to look for an ID tag or sticker with the manufacturers name on it.
It's not a Manco
It's not a Funder Wheels either