The nation most favorable to southern independence was probably Napoleon III, who was focused on expanding the influence of France after the defeat of his uncle, the more famous Napoleon, at the Battle of Waterloo. Napoleon wished to establish a presence in Central America, and in fact had invaded Mexico in 1861.
150 years ago today Napoleon proposed to Great Britain and Russia, the two other major European powers, that they halt the carnage in America by proposing a six month armistice followed by mediation. It seems likely that Lincoln for one would not have accepted this, but he never had the opportunity to make the decision. Russia and England would not accept Napoleon's proposal. This was the high point of the Confederate chances for foreign recognition.