During the Revolution France instituted an extremely enlightened policy towards POWs. However not only was the policy not reciprocated by the Allies, but in some instances they took advantage of the policy. By the time of Brumaire, it was clear that this policy was largely a failure. However, as you mention, French policy during the Consulate and Empire was very ambiguous towards POWs, alternating harsh and lenient policies depending on circumstances. On the other hand, Allied policies-- such as the British pontons and on Cabrera in Spain, were equally harsh. The tratment of common soldiers and officers always were different and remained so even during WWII.