in Paris, back in 2014, there was a collection of over 350 posters about bicycles, mostly French, auctioned off. The anon seller had been collecting these over 35 years

https://vintagebicycle.wordpress.com/tag/cycling-posters/
http://christianlegac.over-blog.com/2017/01/quelques-autres-affiches-anciennes-sur-le-theme-velo.html