Hi Phil,
This tune was attempted by all the French pro accordionists, and IMHO not a single one of them was able to make a decent job of it on the French type CBAs. It is one of several French chanson numbers that tend to sound better on a PA. Unfortunately the composer/singer, Georges Ulmer, was a Dane, and sang the tune in his Copenhagen accent, which did not really cut it. That may have been the reason why most musette players tended to play it tongue in cheek. Ulmer pronounces Metro as Metwo, instead of voicing the fricative French r that is a trademark of Parisian French. Most Danes pronounce the letter r the same as Geordies in England. In other words they dont pronounce it at all!
Jerrys version is one of the best Ive heard and I hope he can find the score for you. However, I managed to work this whole tune out in my head as it was so popular, regardless of who wrote it and sang it in whatever accent. It isnt too difficult, and is usually played in C. There is one passage which changes to Cm, but other than that it is fairly straightforward.
Here is a link to the one French accordionist, Maurice Larcange, who IMHO made a half decent job of playing it, but even then he was assisted by a studio orchestra, and a hell of a lot of multi tracking.
FWIW most French CBA players tend to play it too fast, and that together with the now normal two voice americain tuning of their instruments makes it sound pretty thin. PA players tend to take a more leisurely approach to French musette, and although that tends to detract from most musette style tunes (to we CBA types), it often works better for the chanson type of music like this one.
