The Northern Irishman battled to a level par 71 in the first round and admitted his swing was a "work in progress" as he attempted to rectify the issues that saw him miss the cut at the US Open two weeks ago.
Barring a tee-shot into the water on the last, however, the World Number Four showed no signs of swing trouble on Friday as he catapulted himself into a share of the lead alongside Mikko Ilonen, Thongchai Jaidee, Brandon Stone and Jeunghun Wang.
That leading group has 28 European Tour wins between them but with an elite field gathered in Paris as the Open de France becomes the first National Open in continental Europe to celebrate its centenary, the chasing pack was also formidable.
Defending champion Bernd Wiesberger was at four under alongside Nicolas Colsaerts and Anders Hansen, with Joost Luiten, Francesco Molinari, Thomas Pieters and Andy Sullivan a further shot back.
The diversity of the European Tour was on full display with eight different nations represented in the top eight spots on the leaderboard and there were 32 players within five shots of top spot.
McIlroy gave himself looks at birdie on almost every hole with pin-point iron play to make birdies on the third, sixth, seventh, ninth, 13th and 14th. He surrendered his only bogey after finding the water on the last for the second consecutive day and Stone and Wang soon made it a five-way tie at the top.
“It is a good day's work, said McIlroy. "I can't let a bit of a disappointing finish change what was a really good day. Conditions were tough out there. And I felt for the most part, I controlled my ball well.
“It was disappointing to make five at the last, but it's not going to be the last bogey I make this week. It's just one of those things, but hopefully I can get that shot back quickly tomorrow when I start off again, and get back into sole possession of the lead.”
“It doesn't feel very natural at the minute,” added McIlroy referring to his swing. “It's quite mechanical and there's a lot going on in terms of what I'm trying to do. But it feels good. It's in a good groove. I'm concentrating a lot on it. I feel like if I set myself up well with alignment and everything, if I make a good swing, it goes where it should.
"So that's a positive and hopefully I can continue to do that over the next couple of days.”
Scott Hend leads the Australians after his second round of 69 has him at even par and just five shots from the lead although in 25th position. The Queenslander was the only Australian to make the cut.
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