Rental car Winter tyres

They will only have winter tyres if you ask for, and pay for. them. Much better (and cheaper) to take a train to Aachen or Köln and rent there. A car hired there will have an Umwelt Zone sticker too.

Try DOCKX car rentals. https://www.dockx.be/en/

Contact details: https://www.dockx.be/en/contact/

I agree with Becasse. If you want to go into the city you need the environmental sticker and a German car will have winter tyres. By all means check here with a rental company but these two things are essential.

Thalys offering cheap train tickets to Germany