Assuming this is a 40/50 series Motobecane, the condenser is under the magneto flywheel, attached to the stator plate.You shouldn't have to pull the cam to get at it, but you will need a method for holding the flywheel so the nut can be removed - either a piston stop, or a strap wrench.
Careful with that nut, it takes a 3/8" ratchet drive, and is a LEFT HAND thread - turn it clockwise to loosen it. It is also likely to be very tight.
The parts under the flywheel are small, and fidgety. Use correctly sized screwdrivers, and it also might be a good time to go to Sears, and invest in one of their metric mini-wrench sets.