The 31st European Frequency and Time Forum and the 71st consecutive meeting of the IEEE International Frequency Control Symposium will be held as a joint conference in Besancon, France, July 9th-13th 2017. The conference will provide information on recent advances and trends on scientific research, development and manufacturing technology in the area of frequency and time and frequency control. A technical exhibition will be held during the conference, which will be hosted in Micropolis Conference centre, easily reached by ground transportation from downtown Besançon. Scenic city and historic capital of the french horology, Besancon can easily be reached by high speed train from Paris and by car or regular trains from Lyon, Basel or Geneva. The European Frequency and Time Forum (EFTF) was born in 1987 in Besançon, a wonderful small city 400 km south east from Paris.