~~~ most travelers find it is much better to complete.all networking (contacts) in advance than just walking into a shop and asking...

All a shopkeeper needs to know is what you're interested in and they will do a ton of work since many smaller shops no longer cater to eBay seller though, most of the activity is in Paris and Nice being the second productive (though well controlled by a handful of merchants for the past 35-40 years) and, even then; stuff that has been out of sight for just as long pops up when and where least expected.

Here, well documented remnants from a small inventory from a Paris club turned up in Nice last year... now in my collection.