In the Phoney War of 1939 - 1940, the French army, disastrously, defended behind the Maginot LIne after token advances in the Saarland in September 1939.

If the French politicans and top commanders had wished to attack in Spring 1940, before Hitler did in May, to get far they would have had to cross the Rhine. Was this possible with their resources and military skills?

The Rhine was the front line in the South, between Strasbourg and Basle. The German side is forest. An attack further North would entail crossing the industrial Saarland or the Ardennes Hills, which would lead up to the Rhine Gorge or to the industrial area of the Rhineland around Cologne and the Ruhr. Finally, an attack in the North would go through Belgium and Holland, with accompanying political problems as well as creating additional military enemies.

The allied Rhine crossings in 1945 used methods not available in 1940.

I'm interested in what was technically possible, not what should have been done.