Dani Pedrosa repeated his position at the top of the free practice timesheets on Friday afternoon at Le Mans, during a session that saw the top four covered by just 0.166s.
Pedrosa, Jorge Lorenzo
and Marc Marquez have shared wins in the opening three events of this year and likewise dominated much of this afternoon's practice.
But the Spanish top three was broken by Valentino Rossi, who moved from fourth to second with five minutes remaining.
The Italian was then knocked down a spot when rookie Marquez moved into second place, 0.134s behind Repsol Honda team-mate Pedrosa on his final lap.
Rossi remained the top Yamaha rider, a fraction clear of team-mate Lorenzo.
LCR Honda's Stefan Bradl got the better of Monster Yamaha Tech 3's Cal Crutchlow for fifth place, with Ducati team-mates Andrea Dovizioso
and Nicky Hayden
setting almost identical times in seventh and eighth.
The Desmosedicis were half-a-second from the top, with Gresini Honda's Alvaro Bautista in ninth and Aspar CRT star Aleix Espargaro completing a top ten covered by 1.1s.
The temperamental Le Mans weather lived up to its reputation with a rain and hail shower in the closing minutes of the proceeding Moto3 session.
Fortunately the sun was shining once again as the second MotoGP session got underway, although damp patches meant riders were initially reluctant to leave the pits.
Lorenzo proved grip levels were more than adequate by beating Pedrosa's morning best within ten minutes, with Marquez edging ahead shortly after.
The 20-year-old rookie ruled the session until just after the halfway point, when Lorenzo - whom Marquez tangled with at Jerez - put Yamaha back on top. Pedrosa returned to the top on the brink of the final ten minutes, then set his best time on his 21st and final lap.