The censorship motion
Motion or vote of no-confidence.
But here comes the special role of « king maker » of the far right
I don't think the far-right is kingmaker here, they wouldn't work with the left and neither would the left want to work with them. So both the left and right only have Macron's coalition as an option to get a majority. That makes him with his "center"-coalition the kingmaker, they get to decide if they want to work with the left or right and it looks like he chose the right.
Macron has said he doesn't talk to RN or LFI. If he wanted to work with the left he would accept the candidate from the NFP who already more or less agreed to keep the LFI out of the government, but he chose a Republican who's presumably going to talk to the RN for him to get their support.
The parties in the NFP already said that they'll initiate a motion of no confidence for Barnier.