Lavitto, 27, led with six birdies on the front nine in Prague on Sunday, turning a one-shot deficit overnight behind Svensson into a three-shot lead.
Jesper Svensson came back with a birdie on the 10th and when Ravetto bogeyed the 12th the two were just one shot apart, with both making birdies on the 13th and 15th before the crucial moment arrived.
Swenson had trouble hitting his tee shot on the 16th hole for the second straight day, but in stark contrast to his amazing rescue performance on Saturday, when he hit a 3-wood 311 yards to the center of the fairway, this time it took him four shots to reach the green and then three-putted.
Lavitto pushed his approach from just in front of the green for birdie, moving to 23 under and taking a four-shot lead, which he has maintained ever since.
He said: “I felt good all week and we had a strategy to just go and have fun and it worked out well. Of course, I had some stress and my hands were shaking but that's what you practice for.
“After I drove down the middle of the fairway and walked up to the 18th hole, I was so emotional that I almost broke down and started crying on the fairway. When I saw my caddie and my girlfriend, I couldn’t hold it in any longer.
“I'm sure we'll celebrate – we're French, we know how to do it! Something could happen tonight in Prague and maybe next week in Paris.”
Scotland's Richie Ramsay tied for third at 18 under with fellow Ravetto players Adrien Saddier and Frederic Lacroix. British trio Brandon Robinson Thompson, Alex Fitzpatrick and Paul Waring tied for sixth at 16 under with Austria's Bernd Wiesberger.
