I can't think of anything off the top of my head except for some romance novels, but if you are looking for books that are written in English that were sympathetic to the French side, you might find some books by American authors, seeing as how we were allied to the French for part of that time. Maybe look up the War of 1812, since that's what we call it.
The 1812 war was nothing to do with the Napoleonic Wars though - iirc, it kicked off, because a United States, already becoming aggressive & expansionist attacked Canada, hoping to annex it.
A (possibly former) US Army Colonel, who is also a qualified military historian has written an Alternate History novel - Redcoat's Revenge, after having learnt that Horse Guards (British Army HQ in London) asked Sir Arthur Wellesly to sail over and take command of the British Forces fighting the US in 1812 - The Iron Duke declined, as he wanted to finish dealing with Napoleon.
The Novel has him accepting, and taking several battalions of his Veterans from Spain with him. A Lot of book reviewers have been horrified, as apparantly even the real version of the 1812 War was a close thing for the US, and that wasnt something they knew - but add the Iron Duke, and a few thousand Peninsula Vets to add backbone to the British Forces fighting the US Army, and you are seriously looking at either the total annihilation of the United States, or a huge reduction to a rump state, a shadow of its former self.
Most of the US Army in 1812 simply didn't have any combat experience, and had never fought European Troops at the top of their game. And make no mistake - the Peninsula Vets by 1812 were vicious, ruthless, highly disciplined, highly trained, and highly experienced Killing Machines who had spent the last 6 or 7 years turning French Columns and Regiments into bloody horror - The experienced Peninsula Companies could also generally fire 1 extra shot per minute more than any other troops. And of course, unlike many, the Iron Duke seems to have approved of the 95th Rifles, so veteran companies of Riflemen would have made the US Army have an even worse day. the 95th Rifles are effectively the birth of the modern Infantryman, highly mobile, using fire & manoeuvre etc.