I agree with mostlyharmless. Were it not for the valiant effort of Belgian forces in the Ardennes, in addition to the failure of the German paratroop assault on Eben Emael, whose garrison wasn't forced to surrender until 16 June, the French could not have held back the German assault at the Meuse, despite all their preparation. French doctrine was far too heavily wedded to the Maginot Line, and if these two events hadn't occured, and the Germans had been able to cross the Meuse between 12-15 May, there wasn't anything in place to stop them. The French had more heavily armoured and gunned tanks than the Germans, but the panzer forces had speed on their side. Had the Germans been able to break Belgian defences in the opening 48 hours, they surely wouldn't have been halted at the Oise-Sambre line (OTL Battle of Chauncy) in late June '40, and Stalin would never have broken his non-aggression pact with Hitler on its first anniversary.
It was certainly a hard slog for all sides, those three years. Though massed armoured columns had smashed Poland in the opening days of the war within four weeks, once Germany faced foes its equal on the battlefield, the European War became a slightly more mobile version of the Great War on both the Western and Eastern Fronts. Tank battles on both fronts proved to be nothing more than a mechanised version of the trench warfare of a generation before.
When the von Rundstedt junta government finally ordered the Wehrmacht to lay down its arms on 21 May 1942, there was no discussion on the Anglo-French side of a "victors' peace." Stalin wanted to crack down on Germany, even break it into several different independent states, but Britian and France would have none of that. The lessons of Versailles were loud and clear to them, that a Germany made prostrate is more dangerous than a strong, prosperous German state in central Europe would be. This was also the view advocated by the US, acting a neutral observer at the peace talks held in Oslo during the summer of 1942.
Though Germany has surrendered, they found themselves in a rather strong position at these talks. Their forces on 21 May '42 are battered, yet despite the loss of East Prussia outside the Könisberg pocket, they still maintain control over significant amounts of foreign territory, having held Allied forces at the Meuse for several months in the West, and having prevented (with heavy losses) the Soviet capture on Posen (Poznan).
As we all know, the Treaty of Oslo signed in Sept 42 stipulated the following:
The USSR receives the Baltic states and East Prussia (all areas considered liable to side with a resugent Germany). The Karelian areas of Finland conquered in '40 are to be returned to Finland (for leaving the Axis), though Petsamo is to remain in Russian hands.
Poland will be resurrected and retain its former territory, minus Poznan province.
Germany will lose the Saar to France and East Prussia to the USSR, yet regain Posen (Poznan) province from Poland. An internationally-monitored plebiscite will be held to determine whether the former Austria will remain in the Reich. A "yes" vote on independence will be guaranteed by all Allied Powers, with military force if necessary.
All Italian colonies fall under joint Anglo-French control.