The 29-year old French striker has joined as a free agent after leaving Leicester City and Charlton manager Chris Powell is excited about his latest addition.
"I came across Yann at Leicester and he was a free agent," said Powell.
"He does have good attributes and good qualities, and he's a bit different to what we already have in the striking department.
"Aerially he's very strong and he's a good finisher. It never really worked out for him at Leicester, and it does happen to some players at one particular club when it doesn't always work out for them.
"So, he has a fresh chance here at Charlton, and we'll have to work on his fitness and make sure he's ready."