Fell completely by chance on this article, I invite track fans to throw a look. In summary, many insurance policies cover you on track if it is not about competition or timed event. But last February, following an accident on the track, the Paris court issued a judgment indicating that the participant in a ""club day"" was considered in the ""conditions of competition"".
The conclusion is that it is highly recommended to have a certificate from your insurance clearly stating that you are covered on the circuit, and if not to take the minimum liability insurance offered by the organizers.
The full article: http://www.juritravail.com/Actualite/sport/Id/84401