In Germany you need a second pair of shoes + a small towel + you can`t do curls in the squat rack.
Yep. My gym has a sign at the entrance reminding members they need to have another pair of shoes to train in that are dedicated indoor sports shoes and haven't been worn outside.
About 70% of the people take notice of this. I do because I'm not an asshole.
There's also a sign (there was - it's been removed recently) that says "For the comfort and consideration of ALL gym members, we request that all members speak in German." There is a large expat Russian population where I live - they tend to take over a bit and will usually speak Russian to each other. I guess it was for their benefit.
(I've seen people curling in the squat racks here though)