Collective barter days are organized each year to promote the reuse of used objects. The goal is to reduce the quantity of waste produced by people (other than household trash) by encouraging them to dispose of it in a completely different way. The idea is to create a common space that allows people to get rid of these objects by exchanging them with other members of the community. In addition to supporting mutual aid in the community and raising awareness among the population about material recovery, this helps reduce the unnecessary waste of objects that are still in good condition. Objects such as books, crockery, tools or gardening items can thus be given a second life.