A penalty clause which is included in a preliminary sales agreement of immovable property is an accessory to the sales contract. The clause is called upon only when the buyer fails to carry out its obligation to sign the final sales agreement before a notary and pay the purchase price. The penalty clause therefore has no independent existence from the private sales agreement. In the absence of a choice of court clause, the international jurisdiction over a claim related to that penalty clause is determined pursuant to Art. 5(1) Brussels I Regulation.
Short critique
Unfortunately we do not have more information on the facts of the case.