  We consider a particle system studied by E. Brunet and B. Derrida, which
evolves according to a branching mechanism with selection of the fittest
keeping the population size fixed and equal to $N$. The particles remain
grouped and move like a travelling front driven by a random noise with a
deterministic speed. Because of its mean-field structure, the model can be
further analysed as $N \to \infty$. We focus on the case where the noise lies
in the max-domain of attraction of the Weibull extreme value distribution and
show that under mild conditions the correction to the speed has universal
features depending on the tail probabilities.
