Widebody; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Type 8000
Situational Awareness; Confusion
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Flight Crew Became Reoriented
Airport; Human Factors
We landed in CYMX on runway 24; then exited on B4 taxiway.  CYMX is an uncontrolled field with a FSS that provides advisory information which is Mirabel radio.  We were asked to verify we were on B6 taxiway by Mirabel radio and we then notified them we were on B4.  Mirabel radio said that B4 was NOTAMed closed and asked if we could turn on the runway and taxi via B6 to the ramp.  We were only slightly in the throat or mouth of the taxiway but was not able to make a turn back to the runway safely.  We requested a tug to push back off of B4 onto the runway so we could taxi via B6.  About 3 minutes later; Mirabel radio then said the vehicles had moved at the intersection of B4 and Bravo and relayed information it was safe to taxi to the ramp using B4 taxiway.  We continued to the ramp with no further problems. We missed the NOTAM for taxiway B4 in the paperwork. Things that contributed to this was the poor airport signs and lighting and the unfamiliarity of the airport in a foreign country and their procedures. There were also no barricades of any kind for the closed taxiway. The men and equipment were at the end of the taxiway at the intersection of B4 and Bravo.  We did not see them in the distance until turning on that taxiway. It also was not in the most current ATIS information.  In the future; I realize I should be more careful reading the NOTAMs and being aware of closed taxiways and runways.
Widebody aircraft Pilot reported they taxied onto closed taxiway.