American Brandon McNulty took the overall lead of the Paris-Nice stage race on Tuesday when his UAE Team Emirates won the team time-trial as aerodynamic helmets and speeding drones also hit the headlines.

Pre-race favourite Primoz Roglic of Bora-Hansgrohe dropped 54sec on McNulty and perhaps more crucially 30sec on his key rivals the Belgian Remco Evenepoel of Soudal Quick-Step and Egan Bernal of Ineos Grenadiers.

McNulty leads Evenepoel by 18sec in the overall standings and Bernal by 20sec, with Paris-Nice expected to be decided on two mountainous stages in the Nice back country at the weekend.

The giant yellow aerodynamic helmet used by Jonas Vingegaard at Italy's Tirreno-Adriatico on Monday was used again at the Paris-Nice on Tuesday by the Dane's Visma-Lease a Bike team, but cycling's regulator the UCI said it will examine the matter.

"We want to make sure it assures the security of the rider in case of a fall, the tendency seems be to assure speed," a statement said of the helmet.

Visma came sixth on the day, 38sec from UAE's winning pace in a race where teams of seven riders embarked at four-minute intervals on a 26.9km course around the central French town of Auxerre.

In another first, drones raced alongside the teams at up 65kph, zipping along the banks of a section of the Yonne river, offering a far more pacey impression of how fast the peloton actually moves for television viewers.

Wednesday's fourth stage takes in seven hills in a spectacular 183km ride through the Beaujolais wine-growing region.

The last of the climbs stretches 3km with a challenging 7.7 percent average gradient.