For over 40 years, as part of a Franco-Egyptian consortium, Bouygues Travaux Publics has been furthering the development of North Africa's largest city through the design and construction of the Cairo metro. More than 80 kilometres of metro lines are already in service. Lines 1 and 2 linking the north and south of the capital have been completed, while line 3 is still partly under construction. This will link the left bank of the Nile to Cairo airport, crossing the capital from east to west, and will add to the existing network.

In 2015 and 2016, the National Authority for Tunnels once again called on the consortium for the construction of phase 4A, now completed, and phase 3 of this new line. Line 3 involves the construction of civil engineering works for 17.7 kilometres of new line and 15 new stations – eight underground, five overhead and two at ground level. Built in several stages and phases, the Cairo metro is beset by all the contemporary challenges of tunnel boring: a dense urban area with a tangled web of networks, mixed terrain and numerous crossings beneath the Nile.