Hamburg is 6 hours ahead of Montreal
Best overlap: 8:00 AM to 12:00 PM in Montreal is 2:00 PM to 6:00 PM in Hamburg.
Montreal and Hamburg overlap from 8:00 AM to 12:00 PM (Montreal) to the equivalent 2:00 PM to 6:00 PM in Hamburg — that's your meeting window. Roughly 4 hours of shared hours means scheduling takes a little care — 8:00 AM in Montreal / 2:00 PM in Hamburg is a safe default.