It was probably their standard service rifles rather than machine guns. If it was around the mid 90s, the last three years, or some other period in-between with heightened terrorist threat, they were there for your security.
Unlike US policemen, French soldiers have never killed civilians until now, so you should feel quite safe when seeing them. They also don't arrest you, act aggressive or interact at all with civilians unlike border guards, so I don't see any link with the current topic.
Your comparison of US Policemen and French soldiers isn't fair. I've known a couple people from France of Algerian descent, you can imagine their opinion of French police isn't too dissimilar of yours about US police.
I was talking about the soldiers though, and how they are actually harmless to civilians.
Police is of course a different matter, even though they still are far less lethal than in the US. As far as I know, in the US soldiers don't patrol the streets and their role is taken by the police force however, so that's why I compared them. My wife is not from Europe and I live in the "Arab district" of my city, so I have a reasonably good understanding of how our police force works.
I've been back to Canada a few times since, always with great trouble at the border. 2 hour plus interview. It completely ended an LTR that I had with a Canadian (I lived close to the border at the time) and the idea of emigrating there.
I don't go back, because it's not worth it and honestly it's Canada's loss, not mine.
https://en.wikipedia.org/wiki/2015_Thalys_train_attack
https://en.wikipedia.org/wiki/January_2015_%C3%8Ele-de-Franc...
Submachine guns are automatic pistols, which is to say they fire lower power pistol ammunition, and, like pistols, usually have shorter barrels than rifles. Typically also have accuracy comparable to pistols rather than rifles.
That is Charles de Gaulle Airport, but I have seen the same type of soldier at train stations in France. Regardless of what it's called, that is the type of weapon they have.
And I think that when we demand respect towards proper terminology from people in other fields, we should have the courtesy to do the same. It is similar to calling a monitor a PC or a computer case a hard drive. And being afraid of weapons does not matter here, quite many people are afraid of computers also.