Frantz is also renowned for his talents as a coaching trainer and is considered to be one of the iniators of the "scientific approach" to training in France. He was among the first to emphasize physical training and to introduce the use of body-building. During the 1970s he was responsible of the formation organized for aspiring pro managers by the Fédération Française de Football where he taught the likes of Aimé Jacquet, Roger Lemerre and Guy Roux. In Alsace, he also was influential in Arsène Wenger's development as a manager. In 2001, he was the recipient of the "Trophée Georges Boulogne" to honour his achievements as an educator and trainer.