Factual error: When the raging Tiger is shooting around we can see that the muzzle brake of his gun stands still although it should be moving back and forth.
Continuity mistake: Don Rickles is assembling the .30 calibre machine gun onto its tripod prior to the action in the French village. Neither he nor his co-gunner have any visible anmmunition. The scene changes, the comes back to the .30 calibre machine gun, which is set up on its tripod and is loaded with a belt of ammunition. Where did the ammunition come from?
Continuity mistake: When the guys are making a "deal" with the tiger tank commander, Big Joe's left hand on the muzzle of the tigers gun changes positions between shots.
Deliberate mistake: The German tanks in this movie are not really Tiger tanks. They are Russian T-34's made to look like Tigers. The T-34's are done up very realistically, including Zimmerit (the wavy pattern on the hull of the tiger), which was an anti-magnetic paste put on the tank.
Answer: It's a Yugoslav Soko 522 Ikarus.