Around 50 people were on hand as Le Pen arrived at a shipping company in the western town of Dol-de-Bretagne, hurling eggs and shouting "out with fascists".
None of the eggs hit their target as bodyguards hustled Le Pen, 48, into the building.
France's western Brittany region is not a stronghold of Le Pen's National Front, handing her only 15 percent of the vote in the April 23 first round of the election.
Her centrist rival Emmanuel Macron, 39, scored 29 per cent in the region.
Macron is tipped to win Sunday's vote by a roughly 20- point margin.