The 24-year-old captained Ashanti Gold to win the 2015 edition of Ghana Premier League.
"We're pleased to announce the signing of Ghanaian defender Lawrence Lartey. He signed a three-year deal with us from Ajax Cape Town and we wish him very well in his stay here in Tunisia," a club statement read.
Lartey expressed his happiness after he was introduced to the supporters and media.
"It's a big opportunity for me to once again make a name here in Tunisia. I thank anyone who played a role to see this dream become a reality. I thank the supporters and teammates of Ajax Cape Town too," Lartey said.
"I am here to do my best and hope my time here will be joyful. I will do my best to help Club Africain to achieve success in all competitions," he added.