It was the 31-year-old American's 16th Grand Slam title win, taking her to within two of Chris Evert and Martina Navratilova who are tied for fourth on the all-time list.
And it underscored her near total domination of the women's game, having won three of the last four Grand Slam titles -- at Wimbledon, the US and French Opens -- and reaching the quarter-finals at the Australian Open.
For Sharapova, it was a 10th straight loss to her American nemesis dating back to 2004 when she defeated her in the Wimbledon final and the WTA Championships when she was just 17-years-old.
"But I want to come back next year because I adore Paris and I adore the public here. I want to win here again. I spend a lot of time here (In Paris) ... And I think I am becoming a Parisienne."
Sharapova said:"I played a great tournament, but ran into a really tough opponent today. She has been playing so well this year and the whole of last year as well.
"But this court has brought me so many nice memories. Last year, was so incredible to win and to be back as one of the last two players was great."
Williams was the strong favourite, having won 13 times for two defeats against the Russian and stormed into the final for the loss of just one set, taking her career-best winning streak to 31.
Sharapova though was on a 13-match win run at Roland Garros, having finally come to terms with the demands of claycourt tennis last year when she defeated Sara Errani in the final.
