Hamilton crossed the line 18 seconds ahead of team-mate Valtteri Bottas, taking another step towards retaining his title at Circuit Paul Ricard.
The five-time F1 champion got off to a slick start and continued to fly after switching from medium to hard tyres on lap 25 of 53 on a warm day in Le Castelle.
The only frustration for Hamilton will be that Vettel stole the point for the fastest lap late on, but this triumph was another display of the reigning champion’s unrivalled brilliance this season.
“It has been a really good weekend – I have been racing a long time and it never gets old and it is such a challenge out there, and finding the edge and building the gap,” said Hamilton.
“We are creating history together and so proud to be part of this team. I am hot. It is a beautiful day and the track is awesome and there is some technical areas.
“It wasn’t easy at all and everything is on the edge. I had quite big blisters on the front two tyres – but this has been the best start of the year.”
Checkout the World Championship Standings after French Grand Prix
Lewis Hamilton (Gbr) Mercedes GP 187pts
Valtteri Bottas (Fin) Mercedes GP 151
Sebastian Vettel (Ger) Ferrari 111
Max Verstappen (Ned) Red Bull 100
Charles Leclerc (Mon) Ferrari 87
Pierre Gasly (Fra) Red Bull 36
Carlos Sainz (Spa) McLaren 26
Daniel Ricciardo (Aus) Renault 22