The French electricity-transmission-system operator, RTE, provides a public service: guaranteeing a constant supply of electricity throughout France, with the same standard of service, thanks to the efforts of its 9,500-strong staff. RTE manages electricity flows, balancing production and consumption in real time. RTE maintains and develops the high and extra-high voltage grid (from 63,000 to 400,000 volts) which includes nearly 100,000 kilometres of overhead lines, 7,000 kilometres of underground lines, 2,900 operational, some jointly operated, substations, and around fifty cross-border lines. With 37 interconnections, the French grid is the most extensive in Europe. RTE is an independent and neutral industrial operator which optimises and transforms its grid to connect electricity-production facilities for any future energy choices. Through expertise and reporting, RTE informs the decisions made by the public authorities.