Z7 Operation Rembrandt (1966)

Original title: Rembrandt 7 antwortet nicht

A German scientist takes refuge in an unnamed South American country, and finishes the development of a weapon of mass destruction. Lesky, is assistant, is paid by a Chinese spy ring to abduct the scientist, and appropriate the weapon. Super agent Z7's mission is to find them and prevent that, which he does - at a cost of a number of lives.