One of the highly-reported actions that led to this was folks actually dropping out to avoid vote splitting that would help the far right. I imagine we have some races that would benefit from this unified front:
Since then, more than 200 candidates confirmed they would not stand in the second round to avoid splitting the anti-RN vote, according to local media estimates. Protests also swept the country as demonstrators called on voters to turn out against the RN, with marches in the French capital on Wednesday.