I'm ignorant of French politics so i'll shut up..soon..over here we have "The monster raving loony party" @c, which is the party you vote for if you don't like the main B*st+-*s,er..competitors..so to spoil the vote here you'd get a candidate who wore silly hats and advocates free toffee for all etc.
This is who i'd vote for in the situation you mentioned.
Accuracy,you say? hmm interesting concept..