Macron was economy minister under Socialist president Francois Hollande until he resigned this year to create his own political movement and stand as an independent candidate for next year's presidential election.
In the poll released on Tuesday, he became the most popular of 25 leading French politicians on a 35 percent approval rating, unchanged from a month ago.
That put him ahead of second-placed Alain Juppe, down 4 points at 33 percent, and ahead of Fillon, who lost 6 percentage points of popularity to stand at 31 percent.
In late November, Fillon beat Juppe to win the conservative nomination to contest next year's French presidential election.
Far-right National Front leader Marine Le Pen, in fourth place, saw her popularity rating increase by 1 percentage points to 27 percent.
Opinion polls on voting intentions show Fillon and Le Pen coming first and second in next year's first round of presidential election voting in April, and contesting a second round run-off vote in May, with Fillon seen likely to win the presidency with a two thirds majority.