The construction of the Rance tidal power plant was initiated in 1960. The project involved building a dam 330 metres long in which the turbines were to be housed, a lock to allow the passage of small craft, a rockfill dam 165 metres long and a mobile weir with 6 gates to rapidly balance the levels for the emptying and filling of the reservoir.
The first work sites got under way in 1961. For the sake of convenience and safety, it was decided to erect the structure while ensuring that the construction site was dry. This mean having to build two temporary dams, one on the sea side and the other on the estuary side, in order to protect the structure from water. The work was to last two years. In July 1963, the Rance was cut off from the ocean and the land dried for the whole duration of the construction of the dam which was to require another three years of work. Finally, between August 1966 and the end of 1967, the 24 bulb sets of the power plant were connected to the 225 kV transmission network.