'End of the fairy tale': Summer of discontent hits Macron's reputation

"He [Macron] hasn't convinced enough people that what he's doing is not just franco-francais, that he's not just pursuing a French agenda and dressing it up in European clothing," said Charles Grant, director of the London-based Centre for European Reform.

"He's still someone who makes the weather in Europe because he's almost the only outstanding leader there is, but the downside is he's on his own," he said.

Grand EU ambitions also yield little political gain at home, where issues like the economy and immigration dominate voters' concerns, according to polls.

Even though few analysts expect the Benalla affair to seriously disrupt Macron's reform drive, including to pension financing and public services, he risks having to sell them to a more hostile audience.

"As every French reforming politician has discovered for the last 30 years... these are not easy or popular things to do, especially when you're cutting taxes for the rich," Grant said.