Les Bleus' title defence has been undermined by poor goalkicking but Yachvili was virtually infallible, booting eight from nine for a personal haul of 18 points.
Much of the damage was done in the first half as France swept into a 31-3 lead after the first quarter before going into the break 41-10 ahead.
At that point Bernard Laporte's side looked well on course to eclipse their record win over Italy, a 60-13 triumph in Toulon in 1967.
That scenario became increasingly likely when Saracens back Thomas Castaignede broke through poor Italian defence to score France's sixth try moments after half-time.
But Italy battled back and finally emerged as an attacking force in the final stages, long after the game was beyond their reach.
Full-back Mirco Bergamasco went over for the Italians second try of the game before Aaron Persico touched down soon after to bring the Stadio Flaminio crowd to their feet.
France responded with another score of their own though, Aurelien Rougerie scoring his second of the match in the corner.
Unfortunately for Yachvili the angle and distance left him a little too much to do and his touchline-kick sailed just wide, his only miss of the match.
The final word went to the Italians, who battled back bravely from their first-half mauling.
Number eight Matthew Phillips sent the supporters home in better spirits with a try from the final attack of the match.