The move will not necessarily lead to any major political shift, but signals a desire for Macron to try to move beyond last year's unpopular pension and immigration reforms and improve his centrist party's chances in the June EU ballot.
Opinion polls show Macron's camp trailing far-right leader Marine Le Pen's party by around eight to ten percentage points.
Attal, a close Macron ally who became a household name as government spokesman during the COVID pandemic, will replace outgoing Prime Minister Elisabeth Borne, RTL radio and BFM TV said.
There was no immediate official confirmation of the widely expected move.
One of the country's most popular politicians in recent opinion polls, Attal has made a name for himself as a savvy minister, at ease on radio shows and in parliament.
He will be France's youngest prime minister and the first to be openly gay.
"Gabriel Attal is a bit like the Macron of 2017," said MP Patrick Vignal, referring to the point at which the President first took office as the youngest leader in modern French history, and at the time a popular figure among voters.
Macron has struggled to deal with a more turbulent parliament since losing his absolute majority shortly after being re-elected in 2022.
"The Macron-Attal duo can bring a new lease of life (to the government)," said Harris Interactive pollster Jean-Daniel Levy.
But opposition leaders were quick to say they did not expect much from the change in prime minister, with Macron himself taking on much of the decision-making.
"Elisabeth Borne, Gabriel Attal or someone else, I don't care, it will just be the same policies," Socialist Party leader Olivier Faure told France Inter radio.
