339052 would be 3rd day of the 39th week in 1970, frame #52.
The brakes look like MAFAC Competition, rather than Racer. It's great that you have all of the touring bits - fenders, racks, etc. Get a set of wheels and a new saddle and you'll have a rare French tourer. Definitely replace the rear derailleur.
Look at the 1971 catalog here:
https://labibleduvelocataloguesgitane.blogspot.com/
__________________
72 Fuji Finest 72+76 Super Course, 72 Gitane Tour de France, 74 P-10 & 79 Tandem Paramounts, 76 Grand Jubile,84 Raleigh Alyeska, 84 Voyageur SP, 85 Miyata Sport 10 mixte 89 Cannondale ST400 and a queue