Congrats!!! I can't help but be a little bit envious. A PX-10 is an absolute classic. The very top of my wish list. Enjoy it!
Well, the tires are a biggie, but not the only thing.
Tubular tires or "sew ups" such as those on your PX-10 are well-regarded for their ride qualities, but they're not the easiest thing to work with. The tire is stitched closed around an innertube, and the combined tire & tube are glued to the rim. If you get a flat, you need to remove the tire, open up the stitching, repair the tube, then sew the tire back up and re-glue it to the rim. Compared to a common "clincher" tire, it's a lot of work. It's daunting for a beginner and not the kind of thing you want to learn on the roadside when you get your first flat. I'd strongly recommend you keep an eye out for a used set of period-correct clincher wheels.
Even with the tires aside, old French bikes have a lot of idiosyncrasies. The French had their own size & threading standards, so many parts aren't easily interchangeable with non-French bikes. Sometimes you'll find a mix of French and other specs on a bike (particularly freewheels), so be careful not to strip or force anything. And on a related note, non-French tooling can even strip or damage French parts -- notably by using the wrong kind of crank puller.
Sheldon Brown's got some good info on French bikes on his web site. It's a good read for starters.
French Bicycles
Because of the quirks of French bikes, if you ever take this bike to a shop for service,
make sure it's a shop that knows old bikes!!!