The electrical outlets Barney rewires are designed for American plugs and would not be found in a European building.
During the opening tape scene, Phelps is not walking through a warehouse, it is a ship with gangplank and porthole windows.
At 01 :06 while walking through a warehouse during the opening "tape scene," Jim Phelps passes a truck with a partially disguised Paramount logo on the door. Season 4 was filmed at Paramount Studios.
While running from a bomb that will go off at any moment, the last guard out of the room rather politely (considering the circumstances) pulls the door closed.