French studies in the 1960's were supervised by the French Space Agency, CNES, and developed along two paths. Path 1 was a manned hypersonic booster stage, with upper stages coming in manned or unmanned variants according to the mission. Path 2 was more conservative, with either the Path 1 booster or an expendable booster launching a small re-entry vehicle - a 'Space Taxi'.

Dassault studies in 1963 envisioned a Mach 4 booster powered by turboramjets, with the Space Taxi being launched from it and continuing to orbit. The Minstral design by Nord Aviation was a joint project with SNECMA, CNES, ERNO, and the German Space Agency. This used a delta-winged air breathing first stage, and a lifting body second stage. Sud Aviation produced a similar design, but with both stages using delta wings. In support of these studies ERNO conducted drop test of subscale models from a Transall C-160 over the Baltic and Mediterranean.