Two separate capitulation events took place at the time. First, the capitulation to the Allied nations in Reims was signed on 7 May 1945, effective 23:01 CET 8 May. This date is commonly referred to as the V-E Day (Victory in Europe Day) in most western European countries. Joseph Stalin was displeased by this, believing that the German surrender should have been accepted only by the envoy of the USSR Supreme command and signed only in Berlin. Stalin insisted the Reims protocol be considered preliminary, with the main ceremony to be held in Berlin, where Marshal Zhukov was at the time, as the latter recounts in his memoirs:
“[Quoting Stalin:] Today, in Reims, Germans signed the preliminary act on an unconditional surrender. The main contribution, however, was done by Soviet people and not by the Allies, therefore the capitulation must be signed in front of the Supreme Command of all countries of the anti-Hitler coalition, and not only in front of the Supreme Command of Allied Forces. Moreover, I disagree that the surrender was not signed in Berlin, which was the center of Nazi aggression. We agreed with the Allies to consider the Reims protocol as preliminary." - from Wikipedia.