Can unlawful video surveillance be used as evidence for dismissal for misconduct?

On January 7, 2003, Ms [M] was hired by Pharmacie mahoraise as a cashier.
She was dismissed for gross misconduct by letter dated July 19, 2016, and brought an action before the industrial tribunal to contest the dismissal and obtain payment of various sums in severance pay and damages for dismissal without real and serious cause.