The sentence concluded that Fillon paid his wife and children, as well as Joulaud, hundreds of thousands of euros of public payroll for little or no work.
Fillon was sentenced to five years in prison, three of them suspended, as well as a fine of 375,000 euros ($ 423,000) and a ten-year ban on running for elections.
His wife Penelope was sentenced to a three-year suspended prison sentence and a fine of € 375,000.
The Fillons and their co-defendant were also ordered to repay more than a million euros ($ 1.13 million) to the French National Assembly.
Fillon was Prime Minister under President Nicolas Sarkozy between 2007 and 2012.
He rejected the allegations at the time, saying his wife worked for 15 years as his deputy and handled various roles, including managing his schedule and representing him at cultural events. He also said that his daughter and son were employed in similar positions for 15 months and six months respectively, which he said is not illegal, but was a "mistake of judgment".