Martine Beaugrand, the councillor representing the Fabreville district, entered into the race this morning, shortly after the contest opened.
Candidates have until 4:30 p.m. to submit their names to lead the city until the November municipal elections.
The post was left vacant again last Friday when interim mayor Alexandre Duplessis resigned amid revelations that he was the victim of an alleged extortion attempt involving a prostitute.
Duplessis took the job in November, shortly after long-time mayor Gilles Vaillancourt resigned under a cloud of corruption allegations. He was later arrested by the province's anti-corruption unit and charged with a number of offences including gangsterism.
Vaillancourt has maintained their innocence.
Beaugrand has been considered a favourite for the position, but had not confirmed until this morning that she would enter the race.
If, by the end of the day, only one person has come forward as a candidate, that person will become the interim mayor.
If there is more than one candidate, council will vote by secret ballot before the end of the week.
Laval was put under provincial trusteeship in June, not long after a witness at Quebec's corruption inquiry testified that Duplessis and others in the mayor's former party were among the willing participants in a widespread illegal political-financing scheme.
No criminal charges have been laid against Duplessis.