Question about Osram Night Breaker

Normally, yes. I put the bulbs in a Renault Twingo 3, which is almost like the Smart. However, you have to cut the rubber behind the bulbs a bit, because the Night Breaker has a fan behind it. The result is like day and night, really great!

Can be looked up on the Osram homepage. All compatible models are listed there. However, the Night Breakers are not authorised in Switzerland....

I can't say exactly, I use them in a Skoda Citigo (technically identical to VW Up). As the flange can be removed using a bayonet catch, installation is easy, even with a rubber membrane. The fan then looks out from behind the membrane. Incidentally, it is significantly brighter than halogen, and the light pattern is also slightly wider. However, there is no greater risk of glare as there is a good light/dark boundary. All this with only 35 W consumption is really impressive.