US law originated from British Common Law, and even in modern cases you still see it cited once in a while. In other Common Law countries you often them citing from each other as well (an example would be a Singaporean court using an Australian decision as precedent). Are there any examples of something like this happening in an American court?
The Supreme Court has cited a French case at least once, in Ex Parte Garland, 71 U.S. 333 (1866). While France isn't even a common law country, the Court cited a decision there to help define the common European understanding of a royal pardon.
During the Civil War, Congress had required all federal officials to take an oath saying, in most extreme and comprehensive language, that (among many other things) "I have neither sought nor accepted, not attempted to exercise the functions of any office whatever, under any authority or pretended authority in hostility to the United States." They later extended it to all attorneys admitted to the bar of any federal court.
Meanwhile, Mr. A. H. Garland was serving in the Confederate Congress. Fortunately for him, after the war was over, he was pardoned by President Johnson from all the "heavy pains and penalties" for "participation, direct or implied, in the said Rebellion." He then sued to be readmitted to his antebellum job as a federal lawyer without taking the oath, arguing that the Presidential pardon wiped out the crime as if it had never been committed.
A Presidential pardon, the Court said, had the same effect as a royal pardon and amnesty in England. Its exact extent had never been defined in England, so the Court looked into
...how it has been uniformly understood since, and is now understood, by some of the most polished nations of the world. If we turn our attention to France, particularly, so long and so often the sport of political storms and revolutions, we shall find in her jurisprudence abundant light to guide us in our inquiry as to the meaning and effect of the amnesty.
So, they cited "De Villeneuve & Carrette, vol. 1825, 1827, part 1, p. 135" for "the matter of a person named Clemency," where the Court of Cassation ruled that after Clemency had (1) committed theft; (2) been pardoned; and (3) then committed theft again; the second theft had to be pardoned as a first offense. They then cited a case where a person named Girardin had been sentenced to death (which automatically ended his marriage) and then pardoned; the court ruled that the pardon had the effect of restoring his marriage because it "had abolished the past... he is to be regarded as never having been deprived of civil life."
On the basis of these French precedents, among others, the Court ruled that Mr. Garland must be admitted to the bar notwithstanding the oath.