The account was previously held by Fishburn, but FleishmanHillard Fishburn - the agency formed out of a November merger - did not repitch for the work.
The pitch process was run through creativebrief.
In addition to the corporate comms brief, Engine Group-owned MHP will help deliver PR for L'Oréal's CSR programmes, including the L'Oréal–UNESCO For Women in Science programme (2015 award winner Professor Dame Carol Robinson pictured above).
L'Oréal currently works with brand PR agency Dowal Walker, which looks after its products La Roche Posay and Vichy on a retained basis in the UK. L'Oréal's remaining 32 brands each have a team of in-house PRs working on them.
L'Oréal and MHP declined to comment.