Macron got into power on a very small percentage vote of the whole electorate. There is a city/rest of country split in France as there is here. Their only option was the FN, which the opposition could not bring themselves to vote for, so they abstained. This is my reading, anyway - aided by comments from friends and ex-neighbours.
He was rubbish when he was part of government (I lived there then and read the papers) and people remember that. France desperately needs reforming regarding its beaurocracy etc., but he isn't popular enough to swing it. There will be piles of bovine excrement blocking roads and entrances to Mairies etc. plus the2-km per hour tractors blocking the autoroutes. In other words, yes there will be huge public protests.
As an aside, did anyone else pick up on the fact that he has just nationalised Saint Azaire shipyard to stop it being bought by the Italians - 'Free trade? Non, Non, Non!'.