Lewis Hamilton says he is enjoying "beautiful" France after the country's return to the F1 calendar - but of more significance may be the introduction of Mercedes' new '2.1' engine.
While team-mate Valtteri Bottas was restricted to limiting running due to a car glitch, Hamilton topped both of Friday's practice sessions as the French GP officially returned to the Formula 1 schedule after a decade-long absence.
Hamilton is currently a point behind Ferrari rival Sebastian Vettel in the world championship standings. But in a further boost to Hamilton's title prospects, Mercedes have confirmed the introduction of upgraded new power units this weekend.
According to the Silver Arrows, the new engines, billed as a '2.1' spec, are superior to the units they had planned to introduce two weeks ago in Canada before a fault was detected.
Upgrade helps power Hamilton to mighty double
Mercedes detail engine upgrade
"The new engine feels clean and fresh, but we won't really know its full potential until tomorrow when everyone gets to turn their engines up. I'm grateful for the hard work that everyone put into it back in Brixworth," said Hamilton.
"Overall, it was a good session today - now we need to carry on this performance through the weekend."
Technical director James Allison said Mercedes' engine team at Brixworth had "moved mountains to deliver the updated unit in time for France."
Allison added: "The car is behaving well, the tyres seem to be in decent shape and the pace looks alright."
Hamilton finished over half a second clear of the field in second practice as the drivers acclimatized to the Paul Ricard circuit in the south of France.
"This place is beautiful, it's really stunning down here. It's always a challenge when you come to a new circuit, but you're constantly learning new things and I love the challenge of trying to get into the swing of it before everyone else," said Hamilton.
"There's a lot of different lines you can take and it's tricky to find reference points out on the track. Apart from the colourful lines, it's difficult to tell where you are. There's a couple of places for example on the back straight where you're trying to find out where the corner is - it's really hard to see."
Can Red Bull and Ferrari close the gap?
Speaking before Mercedes' engine situation was officially confirmed, Ricciardo told reporters: "They have an upgrade? I hope so because Lewis' time was pretty quick.
"Hopefully they used it today because if they are going to go quicker it looks like everyone is chasing them this weekend!"
Max Verstappen, who finished just behind Ricciardo in third on the P2 timesheet, said: "Mercedes is still a bit faster than us at the moment but it can never be perfect on a Friday on a new track."
The Dutchman said he and Ricciardo ran different set-ups on their respective RB14s during Friday in order to work out which way to best attack the weekend.
"First practice we were a bit different, and then second practice again, just to see what was better," he said.
"I can be quite pleased, especially after the first practice where I didn't run a lot initially and for me was maybe slow to understand the track a bit better.
"I think the pace is good. The car was handling well, maybe it's about the tyres to get them in the window."
Ricciardo also believed Red Bull had enjoyed a "good day".
Another low-key Ferrari Friday
Despite leading the championship, Vettel unusually has now not topped any of F1's 16 Friday practice sessions so far this season and he finished over a second off Hamilton's pace on day one here.
Team-mate Kimi Raikkonen was three tenths quicker, although still behind the Red Bulls himself, and Vettel said his own "so-so" day did not mean there was not decent pace in the SF71-H.
"I think the car is quick - I wasn't able to be quick, but the car is," he admitted. "As simple as that. Sometimes you have these days.
"It's a tricky track. Not easy to get everything right from start to finish. I just didn't find the sweet spot."
But Vettel, who has turned around several problematic Fridays this season into race-winning weekends, is not worried yet and said he found more of a groove on supersoft tyres on the long runs.
"It felt okay, it was fairly consistent," he added. "There wasn't much wrong, I was reasonably happy with it.
"I haven't seen what others did. Sometimes when I was running we looked like we were reasonably competitive, but we are lacking a bit of performance on the short run which we need to unlock and then we should be fine."