When Fowler tells Phuong that Pyle is dead she is leaning back in a chair. First her long hair is hanging down in front, then it moves to the back between shots.
The officer speaking French is true to historical facts: it was mainly the French Foreign Legion fighting in Indochina at the time. However, the troops were predominantly of German origin (ex Wehrmacht and SS soldiers) and there is no detectable German accent in their French. True, this could be a fully French unit, thus no mistake. In live movies and interviews from the time, German accents in French are common.