Originally Posted by
CFDJ
Sorry here are all the updated Tube diameters measured by the OD
TopTube 26mm
Down tube 28mm
seat tube 28mm (with a 26mm seatpost, Maybe not original but it fits well)
Headtube 30.2mm (The headset parts are all threaded french and the sterrer is 22mm)
Those are metric tube diameter, which were most common on French frames prior to the early 80s. Zeus (Spain) frames also used metric threads and diameters.