POD is failure of German invasion of Norway.
British get the order of battle and send aircraft out to spot the German invasion fleet is where it is said to be, the subs lurking outside the British naval harbors are where they are said to be, etc. The British navy destroys 90% of the German surface fleet and an equivalent amount of the German invasion army delegated to Norway.
When the Germans attack in Belgian one month later, the French counter invasion forces are still in La Havre and are thrown into battle, and as they advance forward they are pushed east by refugees from Belgian clogging the roads in front of them, making them perfectly arranged to defend the Luxemburg border.
The Sickel doesn't Snik until after the Dutch, Belgian, French, and British units have been pushed back so far that they are too far south to be cut off.
Italy stays out of the war, the German sub bases are restricted to Germany, Poland, and the Netherlands, Germany doesn't get supplies from France, etc.