The 18-year-old defender came up through the youth ranks at the Ligue 2 club and made his senior debut in January before going on to make 13 appearances.
The Bulls are delighted to have snapped up the young talent, while Sochaux were left bitterly disappointed that they were unable to hold onto him.
"We have been keeping tabs on Ibrahima for quite some time," commented Leipzig sporting director Ralf Rangnick, according to FourFourTwo.
"He is a young and talented player who will strengthen our defence. We are very happy that such a big talent has joined us. We hope he can take the next step in his career here.
"He has a lot of quality for someone of his age and we are convinced he will bring us a lot of joy in the future."
A statement on the French outfit's official website read: "Losing such a promising talent is a major blow for the club. We have taken in his decision with disappointment and a certain bitterness."