Prince Napoléon and Princess Clotilde visited the USA and Canada between 27 July and 26 September 1861. Harper's Weekly's artist prepared two portraits of them, this one based on a photo. On 8 and 9 August he visited rebel General Beauregard. It can be speculated that there were negotiations about French assistance to the rebels and/or inquiries regarding French incursion into Mexico between Messers. Bonaparte and Beauregard.
From eBay; sepia tone removed by gogm.