In 1930, during the French rugby championship, a player named Taillantou brutally tackled an opponent who died as a result. This incident, which came at a critical moment in the history of rugby, was an important first step towards the birth of sports law in France. Magistrates and jurists dealing with the case tried to answer a seemingly simple question: should the right to violence be recognized in sport, or on the contrary, should any injury or death resulting from a sporting act be answerable to the law? The micro-analytical approach adopted here allows us to measure the extent to which the law, by defining the worth of a sporting rule, has contributed to making sport a social activity in its own right.