c2 ac e2 80 a0 probably solved
I think the solution is actually C2 A0, which is the NO-BREAK SPACE. How do you generate it on the Mac ? You press ALT-SPACE. So when I am hitting ALT-7 for a pipe symbol on my german keyboard and then immediately hit SPACE but haven't really let go of ALT yet, I produce that garbage character.
I assume that my other deductions with regard to conversion are then correct.