Actually, France had a very strong army at the time. Two points here:

• when Hitler moved troops in the demilitarized zone, French president hesitated, but he didn't move. Apparently, Hitler took a big gambit as he thought that the French army could have defeated him then and there (no certainty but very possible)
• Germany conquered France very fast but lost half of its tanks and one third of its planes in the process. It was quick, but it was mostly brutal on both sides.

So, unfortunately, a serie of terrible decisions allowed Hitler's Germany victory: an inadapted defense, and a reluctance to attack.

Main issue for Canada as for most of European countries willing to "defend Greenland": US made equipment and systems: either you have a strong stock of spare parts, or we won't stand long. And that's without counting the basic volume advantage of the US military, and that's without counting the prevalence of US cloud based services everywhere in industry and government agencies.