Ligue 1 has improved the most over the past few years. Their top teams have made it far in the Champions League, especially Monaco reaching the Final last year only to be rocked by Porto. This year Lyon could be the next Monaco, and IMO the former are better than the Principality side that lost in the final last year. Lyon play quick attacking football with speed all over the pitch, so they could cause almost anybody problems. I believe how a league's top sides compete in the Champions League is a testament to the overall strength of that respective league in some cases. Monaco and Lyon making waves in the Champions League is due to the rise in competition in Ligue 1, as well as their own respective team decisions.