Francois Fillon's aides used an umbrella to shield him from eggs thrown by protesters in southwest France as the beleaguered conservative fell further behind centrist Emmanuel Macron and far-rightist Marine Le Pen in opinion polls.
The contrast between former frontrunner Mr Fillon, embroiled in a financial scandal, and new favourite Mr Macron was striking on Saturday as both candidates campaigned 29 days before the first round of France's unpredictable presidential election.
Addressing a rally in the French island of La Reunion, in the Indian ocean, Mr Macron departed from typical campaign speeches by inviting members of the audience - including a six-year old who asked him "How do you get to be president?" - on stage to ask questions on a wide range of issues.
"It's historic, we need to decide whether we want to be afraid of the century that has just started ... or want to bring fresh ambition to France," the 39-year-old former investment banker said to chants of "Macron President!"
Mr Macron, a former economy minister to Socialist President Francois Hollande, set up his own centrist party last year.
He has shot to first place in opinion polls since Mr Fillon was put under investigation over suspicions he misused public funds by paying his wife hundreds of thousands of euros as a parliamentary assistant for work she may not have done. Mr Fillon denies any wrongdoing.
Mr Fillon slipped 2.5 percentage points on the week to 17 percent in a BVA poll published on Saturday, which saw Mr Macron getting 26 percent of the first-round vote, up one percentage point from a week ago with Ms Le Pen on 25 percent, down one point.
The number of undecided voters for the first round remains high, with 40 percent of voters still undecided.
The poll showed Mr Macron winning a second round vote with 62 percent of the vote versus 38 percent for Le Pen, who is due to hold a rally in Lille on Sunday.