Par Olivier Duffez :
Ces 3 articles, classés dans l'ordre chronologique inverse, montrent l'évolution des solutions que l'on peut apporter au problème du “duplicate content”.
When you call /slug/ or /slug the same page is served, it would be better for SEO if /slug is redirected to /slug/ or visa versa otherwise search engines consider the two pages as duplicate content which is bad for your page ranking.