Frankfurt is 6 hours ahead of Ottawa
Best overlap: 8:00 AM to 12:00 PM in Ottawa is 2:00 PM to 6:00 PM in Frankfurt.
For the smoothest call, aim inside 8:00 AM to 12:00 PM in Ottawa, i.e. 2:00 PM to 6:00 PM in Frankfurt. Frankfurt is 6 hours ahead of Ottawa, so the practical overlap is about 4 hours — generous enough for meetings, tight enough to be worth booking ahead.