Didn't they requisition every Taxi in Paris to do that, or was that Verdun?
That was Verdun.
The problem with using civilian vehicles was that many were not suitable for military use, which the Germans quickly discovered when they moved Western European cars to the Russian front. Transportation using civilian vehicles works best when you have good roads to drive on, enough men to repair/maintain the vehicles and you're not facing significant enemy interdiction (you don't want to be in a large bus on an open road when enemy aircraft show up). The French moved large parts of the 7th Army into the Netherlands using civilian transport in 1940, but Luftwaffe interdiction caused significant problems and slowed movement down to a crawl after a few days. The withdrawal went more orderly as the Luftwaffe was by that time focussing its strength on supporting the Panzer spearheads.