Before you do anything, check the tank. Its structural and If is has pinholes or is rusted out the bike is junk. If could fold in half if the tank is compromised.
It looks like an av7 engine, can't tell by the photos if it's variated or not. Meaning variable gear ratio pulley/clutch setup...Regardless it's a very common engine and the frame will also accept the more powerful AV10 engine found on later french bikes.
If the frame is good, you'll want to start with getting the engine running. It comes with a crappy gurtner carb, it'll work fine when setup right. But can be extremely finicky. The standard upgrade which also increases power a bit btw is a dellorto 15/15 carb and matching 15mm intake manifold(malossi shorty). It's a great option because if you ever want to increase displacement to a 70cc setup that dellorto carb will work fine on a good mild build(40-45mph or so)
Remember that you will need to tune the carb by rejetting anytime you modify a two stroke, exhaust, carb, air filter....etc..for performance yes, but mainly so you don't seize the engine, too lean fuel/oil mix and the engine locks up.
It's a very simple rebuild if you need to do it. You will most likely need crank seals at the very least, but don't worry about that until you know the engine is...A-seized, so you'll need a rebuild anyway. Or B-you find a crank air leak whilst attempting to get it running.
Model info "should" be on the head tube behind the headlight.
A special puller tool is required to pull off the variator/clutch pulley. It's not expensive.
Our resident motobecane wizard Rebelmoby will no doubt chime in with copious knowledge about your bike very soon. (edited)