you use different pronouns (“vous” or “tu”—cognates to “you” and “thou” in English) depending on the relative status of your interlocutor (and other things)
Dunno about French, but I think that in most languages with such a system the V form is getting rarer and rarer. For example, in Italian the rule used to be that one only used “tu” with friends, family and children/teenagers (of course this is only as precise as one’s definition of “friend”, but still); but nowadays one uses it with everybody except superiors and people obviously (at least a decade) older than oneself (with the weird result that someone in their 20s is more likely to be addressed as “tu” by a stranger in their 40s than by a stranger in their 70s). In English too, addressing people as “Firstname” vs “Mr Lastname” is roughly equivalent, and the latter is becoming rarer and rarer.
Dunno about French, but I think that in most languages with such a system the V form is getting rarer and rarer. For example, in Italian the rule used to be that one only used “tu” with friends, family and children/teenagers (of course this is only as precise as one’s definition of “friend”, but still); but nowadays one uses it with everybody except superiors and people obviously (at least a decade) older than oneself (with the weird result that someone in their 20s is more likely to be addressed as “tu” by a stranger in their 40s than by a stranger in their 70s). In English too, addressing people as “Firstname” vs “Mr Lastname” is roughly equivalent, and the latter is becoming rarer and rarer.
Yup, the usage is following the same evolution in France—there are also similar usages in China (ni vs. nin) that are disappearing.
In Spanish, at least, it varies by region, and some places have dropped the familiar in favor of the formal. English did the same thing.