We have two German Shepherds and 6 (outdoor) cats. Most of the cats won't let the dogs get close enough to them to tell, but 2 of the cats are fine with the dogs and the dogs are fine with them. Our cat, Harley, loves our female Shepherd, Duchess. They sleep together all the time. However the Duke and Duchess both ignore our other cat Friskie and he ignores both of them.

If you're getting this GSD as a puppy, it should be fine...perfectly fine. If he's raised around the cats, there will be no problems. You'll still have to monitor their interaction in the beginning as both sides will be curious about the other.