https://www.pro-velo-geneve.ch/bourse_aux_velos_d_uni_mail_20210418
To sell a bike
Registration: from 10h to 12h
To withdraw its profit or unsold bikes: from 14h to 15h

To buy a bike
sale: from 12h30 to 14h
Note: from 12h for students and PRO VELO members