Full French mobilization has started only four days before the start of the scenario. There are 24 French infantry divisions at start including some far from the Saar region, 2 Mechanized Divisions and 4 armored regiments. However, only 5 of those divisions are within one day's march of the front line on day one of the scenario. The French also have substantial artillery forces.
There are 25 German infantry divisions stationed on the Siegfried Line or in back areas. At start, the Germans have a stronger force actually on the front line.
There are substantial French reinforcements to be added as mobilization continues, whereas there are lesser German units that will be added as reinforcements prior to the fall of Poland.
Three British divisions are available by by turn 3, ie six days after the start of the scenario, with four more to arrive later. It's a hypothetical scenario, so I suppose this BEF will be available for the Saar Offensive.
Here's a general comparison of the typical unit strengths/combat factors, although there are for instance several different French divisional types.