Mantis has a portfolio of managed and branded properties including boutique hotels, eco lodges, game reserves and luxury houseboats. The group also operates a tour division.
Its hotels include Founders Lodge in South Africa and the Draycott Hotel in London, and it is developing the first hotel in St Helena.
Along with the partnership agreement, Accorhotels and Mantis Group are launching the Community Conservation Fund Africa (CCFA), a non-profit organisation that aims to preserve Africa's wildlife and brings together three organisations - Wilderness Foundation, Tusk Trust and African Parks.
Sebastien Bazin, chairman and CEO of Accorhotels, said: "Mantis is a pioneer in customised one-of-a-kind travel services in some of the most imaginative hotels across the world. With this strategic partnership, we are reinforcing the group's footprint in Africa and we have access to a brand with strong roots and heritage, recognised for its commitment to preserve the environment and its prestigious credentials in the hospitality space."
Adrian Gardiner, founder and chairman of the Mantis Group, said: "Accorhotels is one of the fastest growing hotel and travel operators worldwide. This agreement presents an attractive proposition for the Mantis Group to utilise Accorhotels' robust distribution channels and world-wide reach to further develop the hospitality concepts and sustainability projects we have worked so tirelessly to grow. We are excited to embark upon this new chapter alongside Accorhotels where we will act as ambassadors for the development of both our groups' portfolios and offerings."
The acquisition is subject to regulatory approval.