Florence Laizier is a graduate of the Ecole Polytechnique and the Ecole Nationale des Ponts et Chaussées engineering schools.
In 2003, she joined the RATP Group to work on an urban planning project in Paris, followed by metro operations. There, she started as operations manager of lines 4 and 12, and became operation director of line 3 as part of the creation of a new control center.
In 2009, she moved to project management and joined the T7 team in charge of the design and construction phases of a new tramway line, in which she managed safety procedures, purchasing and coordination of the stakeholders.
In 2011, she was appointed general manager of the metro line 6, followed by general manager of the newly automated line 1.
In 2017, she joined RATP Dev, a subsidiary of the RATP group in charge of operations and maintenance of urban and intercity networks in France and abroad, as deputy director of business development and performance. As head of bids department, she oversaw the major bids for railway, buses or subway networks.
In 2020, she joined Vinci Construction as Chief Technical Officer to manage cross-functional activities, such as engineering, innovation, R&D and environment.