The 1st Gebirgs-Division, for one, made extensive use of rafts during their part of the invasion of France, crossing the Oisne/Aisne Canal, Aisne River, Seine River, and Marne River while under fire.
Here are some Gebirgs-Pioneers from a unit of the 1st Gebirgs Division on the Seine:
And on the Aisne, being pulled by a swimming 'Muli':
They were also commonly used to create pontoon bridges for the Gebirgsjagers, since the retreating French had a nasty habit of blowing up their bridges:
Here's a photo of slightly larger infatable raft being utilized by Gebirgsjagers somewhere in Russia:
They were probably used somewhat often in Russia, since the German lines of advance in 1941 and 1942 took them across several rivers and other bodies of water, especially in the Southern sector, where the 1st and 4th Gebirgs-Divisions operated as part of Army Group South.
After the heady days of Blitzkrieg, I imagine that they were used on a smaller scale by Gebirgsjagers on the defensive in Russia, Italy, the Balkans, and especially Finland, which is dotted with lakes and rivers. (For example, for small raids or reconnaisance against enemies on the other side of a body of water.)
I'm sure Patrick can come up with some other photos of river crossings, as well as other areas where Gebirgsjagers might have commonly used inflatable rafts.
On a slightly related note, Gebirgsjagers of the 7. SS-Freiwilligen-Gebirgs-Division 'Prinz Eugen' apparently utilized motorized fast attack boats on the rivers of Yugoslavia while combatting Tito's Partisans in 1943-1945.