It's the first time any political party in France has ever chosen this route to select its candidate (it used to be done by the apparatus).

It's not an election, it's just one party choosing its candidate via an internal choice. There are plenty of parties in France, and plenty of candidates to vote for in the presidential election (6 or 7 already announced on the left, for instance).

Using the word "primary" was just a way to make it understandable as a concept, but it's not exactly the same process as in the USA. The roles of the various institutions are just so different form country to country, even (especially) in Europe, that it's hard to compare at times.

In the long run, we're all dead. John Maynard Keynes