I don't know anything about Velosolex, but I do know that Dia Compe TT levers were originally designed for city bikes and they fit 7/8" bars. They come with shims for road bars. They didn't become TT levers until Lance used them on his TT bike in the TdF. The instructions that come with them show special slotted grips for use on city bikes, but I don't know if you can still get those grips. Cork grips can be made to work with them the same way they can be made to work with barcons.

Velo Orange has some beautiful CLB levers, but you have to buy a whole bike to get them.