The Bourse aux vélos / Bike sale happens I think it’s twice a year once back in September / October and the other time is today!
If you’re looking to pick up a cheap second hand bike then this is for you. In fairness I don’t think the deals are that great and you might be better of looking on LeBonCoin, however with the Bourse aux vélos you can pretty much be sure the bikes haven’t been nicked.
Practical info … it’s happening at Place Viarme from 9:30 this morning.
If you’re really trying for a bargain you might find that after 15:00 people are willing to sell for that little bit cheaper.
If you’re curious how much a new bike will set you back you could just check out the likes of Decathlon with prices starting at around €150 … (There are also a few of bike shops around town once just 100 meters south of commerce) remember buying from a shop you’ll have a guarantee and they’ll be able to repair it if it’s still within warranty (No idea if you’ll have that at the Bourse aux vélos)
You can find out more (in French) here