The women accused Tron, who is mayor of Draveil, and his former deputy, Brigitte Gruel, of abusing them during foot reflexology sessions in Tron's office between 2007 and 2010 that turned into threesomes.
After a four-week trial Tron and Gruel, both aged 61, were acquitted of the charges.
Virginie Ettel, 41, and Eva Loubrieu, 44, testified that they felt powerless to resist being groped and penetrated digitally by Tron because they were afraid of losing their jobs. They said Gruel took part in some of the sessions.
Ettel later resigned, while Loubrieu was fired after being accused of theft.
Reacting to the verdict, Ettel expressed "huge disappointment" and said: "I will not give up the battle I have been fighting for years."
The prosecution, which had called for Tron to be given a six-year prison sentence, has 10 days to appeal.
Tron, who practises reflexology as a hobby, and Gruel had denied the allegations, claiming they were part of a political smear campaign.
The accusations emerged days after Dominique Strauss-Kahn, the former French head of the International Monetary Fund, was arrested in New York in May 2011 on charges of attempting to rape a hotel maid.
The criminal case against Strauss-Kahn later fell apart and he settled the civil case out of court.
But the affair had a knock-on effect in France, leading several women to break their silence about alleged harassment or assault by politicians and other public figures.