More than seven years after the murder of Monegasque billionaire Hélène Pastor, a French appeals court has upheld the son-in-law's life sentence.
The contract killer and his accomplice will also remain in prison for life, the court in Bouches-du-Rhône ruled on Friday.
The lawyer for the Polish son-in-law announced an appeal to the Supreme Court.
Wojciech Janowski was found guilty in October 2018 in the first instance of having ordered the killing of the 77-year-old and her driver.
The Polish honorary consul had made a confession during interrogation, but later revoked it.
Hélène Pastor was gunned down in her car on May 6, 2014 after visiting her son in a hospital in Nice and later died of serious injuries.
Their driver was also killed.
The shooter and his accomplice initially escaped unrecognized.
The Pastor family had amassed a huge fortune with real estate deals in Monaco, where housing is very expensive.
The act caused horror in Monaco and beyond the borders of the small principality on the Mediterranean.