Loss of chance of capital gain: the rigorous proof required by the Court of Cassation

Imagine acquiring a property with the firm intention of reselling it quickly and making a nice capital gain (the profit between the purchase price and the sale price). But then, an unforeseen event – a defect, a neighbour's appeal, a missing document – delays the transaction. You still end up selling, with a significant profit. Can you nevertheless claim compensation for having lost the chance to sell at an even more favourable time? The Court of Cassation responds with a rejection in a decision of 9 February 2010, requiring you to provide a rigorous demonstration of your loss.

This type of litigation is much more common than one might think. In urban centres where prices dance a frantic waltz – Paris leading the way – market fluctuation can represent colossal sums over a few months. But a principle governs our law: any loss must be certain in order to be compensated. Where does certainty begin when we're talking about a hypothetical gain? That is the whole issue of the ruling handed down by the third civil chamber.

We will unravel the thread of this ordinary dispute, delve into the reasoning of the senior judges, and above all draw practical consequences for any owner, tenant or property professional. Because the decision does not merely recall principles: it firmly anchors them in the concrete assessment of a loss that ultimately did not materialise.