Used cycling shoes/spd pedals

Hello
I will be on a trip in Europe in the middle of august, and most likely will stay for 2 nights in Paris, and right now I'm looking for cycling shoes and spd pedals, so I was thinking if anyone could give me some information, where I could possibly find used shoes/pedals in Paris(and maybe some used steel road frames )
I will maybe soon post the other stops in France, that we are planning, but I think the time spent is much less...