An employee of Petit Bateau, bound by a confidentiality clause since 2010, posted on Facebook in April 2014 a photograph of the confidential spring/summer 2015 collection — visible to some 200 professional contacts, competitors included. Dismissed for gross misconduct, she challenged the evidence as unlawfully obtained from her private account. The Cour de cassation (Soc., 30 September 2020, No. 19-12.058), after the Paris Court of Appeal's 2018 ruling, validated the employer's approach: producing evidence that intrudes on the employee's private life is permissible where it is essential to the exercise of the right to evidence and proportionate to the aim pursued — here, defending the legitimate interest in the confidentiality of the business. The article highlights what the decision means for fashion houses and any business built on secrecy: social networks are a major leak vector, and the proportionality test now frames how such leaks can be proven.