I have tapped out a few sets of French aluminum cranks myself, and I am far from an expert. I would also be a bit wary of tapping old steel cranks though. If your Pug still has cottered steel, you could consider replacing your cranks and bottom bracket with a vintage (or modern!) aluminum crank.
There are MANY people here who are fans of the UO-8 Peugeots. I replaced the crank on mine with a Spécialités TA crank:
