I think the problem you having is that the upper rear derailleur jockey wheel is rubbing on the larger cogs. Unfortunately, aside from changing derailleurs, there's not much you can do about it.

Thank you!!! that was what i was really wondering...

mine has the Stronglight cranks as well...
aside from the jockey wheel rubbing, the other noises arent too bad, and it is fun to ride... having a few issues with the brakes too, but nothing too terrible...

found 1978 on the back wheel as well... so, the bike is pretty much the same age as i am...