RPG with Rats as PCs?

I am tryting to remember what the name of that (german?) RPG was where you play a rat in some sort of decrepit house or mall or something. One of the worst enemies would be Cats.

I remember that it used a rather simple mechanic of just d6, some keywords on each chacarter and some… checkboxes I believe.

Rats were of different breeds (tribes?) and one of them were labrats.