According to the Military Atlas, Davout had 75,000 regulars in Paris 29 June 1815. This figure included the 55,000 remnants of the Armee du Nord and the garrison of Paris. He had a further 42,000 National Guard, veterans and Federes.

If these re-inforcements were on the march they do not appear to have reached Paris by the end of June. I do not recall that there were many regulars in the northern fortresses but mostly National Guard?

In any event, anything that took the French army farther from Paris was an advantage to the Allies. Paris at best might have 20,000 regulars of varying quality and nothing between it and Schwarzenberg.

Ron