Sounds like a Gitane Tour de France, Service Course was part of the stickers on all the models I believe. There were 2 models, one with French components and Simplex dropouts, the other with Campagnolo including dropouts. The 3-arm crank doesn't sound right, that was part of the Nuovo Gran Sport group. Brakes would have been Mafac on both models I think, though the one I had came with Campagnolo though I think it was an upgrade as the crossover stop was brazed to the seat stays. Colors I remember were white, purple, green maybe blue.
Typical French frame building: crude but effective. A little heavy as I recall. I could dig up a pic of mine maybe.
Ted Williams
Oakland