We had a thread as the elections that lead up to this occurred which included a very good analysis of why Macron chose as he did by @FrenchDunadan, and this penultimate post:
The answer of about two and a half months is not a shock.
The Right holds the strong hand now to my understanding. They were stopped in round two only by cooperation of the center and left that Macron subsequently poisoned.
I readily admit that French politics and how their system works is foreign to me. I know just enough to be very concerned about instability in general but in particular that this representing a further notch across Europe to the Far Right gaining more power.