This Supreme Court case involved a dispute between Charles B. Dufau, the plaintiff in error, and Jean Henry Couprey's heirs, the defendants in error. The issue at hand was whether or not an agreement made by Dufau to purchase land from Couprey had been legally executed before his death. The court found that although there were some discrepancies with regards to how the contract was written up and signed, it had still been validly entered into prior to Couprey's passing away. Furthermore, they determined that since both parties had acted upon their agreement as if it were binding - such as making payments on the property - then this constituted sufficient evidence of its validity under Louisiana law. As a result of these findings, they ruled in favor of Dufau and ordered that he be allowed to take possession of said land according to terms outlined within their original contract.

In this case, the Supreme Court was asked to decide whether a French land grant in Louisiana should be recognized as valid. The majority opinion held that it should not because the grant had been issued by an authority that did not have jurisdiction over the area at the time of its issuance. Justice Story dissented from this ruling and argued that while there may have been some irregularities with respect to how and when the grant was issued, those issues were irrelevant since they occurred after it had already become effective. He further noted that even if there were irregularities present, they could still be remedied through other legal means such as confirmation proceedings or a bill of review. Ultimately, he concluded that denying recognition of a validly-issued foreign title would undermine public faith in government grants and create uncertainty for all parties involved in similar transactions going forward.