The poll by Ifop Fiducial for publication on Sunday in the Journal du Dimanche newspaper showed Sarkozy still well in the lead with 28 per cent of voting intentions.
The Socialists' Segolene Royal, who if elected would be France's first woman president, had only 23 per cent of first-round voting intentions.
Mar 16: Deadline for presidential candidates to get at least 500 mayors or other elected representatives to sponsor them. Without these, candidates cannot stand.
Mar 19/20: Constitutional Court examines proposals, decides list of official candidates.
Apr 9-20: Official campaign period.
Apr 21: First round presidential voting in overseas territories and departments. Guadeloupe, Martinique, Guyana, Saint-Pierre-et-Miquelon and French Polynesia.
Apr 22: First round of voting on mainland France, the Indian Ocean islands of Reunion and Mayotte and in New Caledonia.
May 5: Second round of overseas voting.
May 6: Second round of mainland voting.
May 17: End of President Chirac's mandate.
Jun 10: First round of parliamentary voting.
Jun 17: Second parliamentary round.
Jun 19: End of out-going parliament.
With official nominations for the race due by next Friday, Chirac has kept open till the last moment the option of running again - despite polls that show he would have no chance of winning.
But in recent weeks he has given several hints that he intends to step down, telling a television interviewer last month that "there is life after politics" and that he hopes to serve France "in another capacity".
The president has also hosted three international meetings on issues known to be close to his heart - Lebanon, the environment and French-African relations - and this week he attended what was widely seen as his farewell EU summit.
"Europe was a fantastic adventure which was not always easy for the French whose deep attachment to their country, history, culture and fatherland is well-known," he told a news conference.
Although this was his last summit, Chirac will attend his final EU meeting in Berlin later in March.