Originally Posted by
San_Son
...To my surprise, the Zeus fixed cup although it is french threaded 35 x 1 mm it is left-handed (it tights to the left) and I've learned it the hard way (after cuting it with a circular saw

) The bottom bracket is 118 x 55GS (Gran Sport)
Furthermore, I have already bought a new Zeus BB, same aspecs 118 x 55C (Criterium) but... A-HA! It doesn't fit, this one are both cups right-handed...
You got yourself metric
SWISS threading going on with that frame, nothing French about it.
I've "forced" an English-threaded BB-UN72 bottom bracket into a 1979 Peugeot's Swiss-threaded frame, but it took considerable back-and-forth action with a long wrench to work it in fully (the cups being aluminum, no alteration to the frame's BB actually occurred).
I don't think that it would have worked using a bottom bracket having only holes for a pin tool instead of robust splines like the Shimano BB.