Lawyer's Duty to Advise: When Real Estate Tax Optimisation Turns into a Nightmare

In Paris, an entrepreneur sells the shares of his company GL Trade and, on the advice of his lawyer, makes a contribution to a family SCI to benefit from rollover relief on the capital gain. Five years later, the tax authorities challenge the arrangement: reassessment, penalties, late payment interest. The entrepreneur then turns against his advisor. This case, decided on 25 June 2025 by the Court of Cassation, highlights a question that gnaws at every investor: how far does the lawyer's liability extend when the law is uncertain?

The ruling provides a firm answer: the legal professional cannot hide behind the debatable nature of a tax position. On the contrary, they must clearly explain the risks and grey areas. A decision that resonates particularly in Paris, where sophisticated real estate arrangements are legion, and which should prompt every owner to redouble their vigilance before signing a bold transaction.

In this article, we will decipher what this 'duty to advise and prudence' concretely implies for lawyers, and above all what you, as a real estate project holder or professional in the sector, must demand from your intermediary. For as this case law reminds us, a mere favourable opinion is not enough.