The European license plates on the cars in the opening sequence are plastered over American-style plate holders, indicating it was filmed in the United States with domestic versions of the automobiles.
When Jim unloads Ginny's groceries from her Mercedes in Switzerland, one of the bags contain a box of American food named 'Stuffin' ', which was not available in Switzerland.
It's never explained why the bad guys insist on Rockford taking the bus out of town when he has his car.
In fact, they take him from his car and drop him off at a bus stop.
In fact, they take him from his car and drop him off at a bus stop.