Disclaimer: First of all I hope this is not a loaded question, in the sense of "I heard the extreme right had a lead in the first round, so how far were they leading and how much is that a stolen election".
As origimbo has pointed out, people were voting with the knowledge that there would be a second round, so taking a leader in 3 way races and pretend that they would have won if you cut there is somewhat disingenuous. The thing is if people would have known there would be only 1 round they would likely have done the tactical voting in round 1 leading to a likely much different outcome.
Though in case you're only interested in the data. Well the French ministry of internal affairs made those data pretty transparent:
https://www.resultats-elections.interieur.gouv.fr/legislatives2024/
click on the region and the subdivision and see the result if you're looking for a particular constituency, but they have also overall data:
https://www.resultats-elections.interieur.gouv.fr/legislatives2024/ensemble_geographique/index.html
and as CDJB mentioned they also have that as json apparently:
https://www.data.gouv.fr/fr/datasets/resultats-du-1er-tour-des-elections-legislatives-2024-par-departement-et-circonscription/#/resources
It's in French, but there should be plenty of translator apps to translate the few uncommon words that aren't apparent from the context. Maybe as a start gauche=left, centre = center, droit = right.