* Supreme Court set to rule on case on Jan. 23
* Lawyer confident that key evidence will be thrown out
* Ruling could call for retrial
MEXICO CITY, Jan 11 (Reuters) - Mexico's Supreme Court this month will review the case of a Frenchwoman imprisoned for kidnapping, and her lawyer is confident a ruling could pave the way for her eventual release.
The panel of five Supreme Court judges is set to issue a ruling on Jan. 23 in the case of Florence Cassez, who was convicted in 2008 of participating in a kidnapping ring and sentenced to 60 years.
Agustin Acosta, the lawyer, said the judges are likely to rule that testimony used to convict Cassez was tainted and call for a re-trial by a lower court.
"If it turns out like this, there is no case, no proof against Florence Cassez. It will be handed to a lower court and the judge will have to absolve her," Acosta said in an interview on Friday. "We are confident that ... Florence will get her freedom back."
In March, Mexico's Supreme Court rejected a bid to release Cassez immediately, but it opened the door to reviewing the evidence in her trial.
The Supreme Court panel will now rule on a motion by Judge Olga Sanchez, who in May said there were "many reasons" to release Cassez.
Cassez, 38, has maintained her innocence. She was arrested in December 2005 at a ranch near Mexico City with her ex-boyfriend, Israel Vallarta, who was accused of heading a kidnapping gang called the Zodiacs.
After the arrest, police forced Cassez to take part in a staged scene of officers freeing kidnap victims. She was portrayed as a kidnapper in the restaged event, which was aired on national television. Police have since admitted their wrongdoing.
Her defense has argued that testimony against her was tainted by the television report that depicted her as a kidnapper.
One of the judges most opposed to freeing Cassez in March has since retired from the court, replaced by a younger, U.S.-educated judge who may be more willing to recognize the argument that her right to a fair trial was compromised, Acosta said.
A ruling to throw out evidence and require a retrial could meet less political resistance than the March motion that called for her immediate release. The prospect of her release has stirred resentment among victims of kidnapping, which often goes unpunished by Mexico's weak justice system.
The conviction has caused a bitter diplomatic dispute with France and a condemnation of Mexican justice, where authorities are often accused of trumping up evidence to win convictions.