The poll found that Macron was set to win 24 percent of the vote in the first round and Le Pen would get 21.5 percent, with his score steady from the last time it was conducted three days earlier while hers was down 1.5 percentage points.
Fillon, who has slowly clawed back some ground lost after being hit by a fake jobs scandal, saw his score in the first round rise half a percentage point to 20 percent.
Melenchon, who would hike taxes on the rich and spend 100 billion euros ($107 billion) of borrowed money on vast housebuilding and renewable energy projects, gained 1.5 points to 19.5 percent as he built further on momentum he has seen after strong performances in television debates.
If Melenchon makes it to the runoff, he is projected to beat both Le Pen and Fillon by comfortable margins although he is seen losing to Macron 41 percent to 59 percent.
The number of people surveyed who expected to definitely turn out for the first round rose to 71 percent, the highest so far during the campaign although that is nonetheless low by historical standards.
($1 = 0.9336 euros)