The left didn't get a majority, so it's just parliamentary politics. It's a bit unusual for France where the biggest party tends to form a government, but that's a political norm we would have been happy to see broken had the Rassemblement national done as well as everyone expected it to.
What is more problematic is that the Cabinet is not allowed to vote in parliamentary matters, which Macron needed in order to marginalize the left. So he fired his Cabinet, so that they formally returned to parliament and could vote. The problem is, of course, that they don't have any replacements, and their roles need to be filled. So now they're voting in parlament while continuing their duties, giving the sleezebag Gabriel Attal the title "Outgoing Prime Minister Gabriel Attal", but not changing anything of substance.
It's not constitutional, but the courts let it slide, because they're as terrified of the French left as Hindenburg was of the Social Democrats.