Man, make a distinction between last season and current season. OK, Nice is not the 3rd best team in France atm, that was based on last season, and in France, not having any top teams behind PSG, things can drastically change form month to month almost. I give you that.
Let's say Lyon is the 3rd best team in Spain. Lyon and Marseille (probably 2nd best) are teams that are weaker than Juve, Napoli, Roma clearly, and Inter probably. This is what most football fans would tell you. Marseille lost 1-6 to Monaco this season. Think about it. Do you think any of those 4 italian teams would go to a poor Monaco and lose 1-6? It's obvious that Ligue 1 teams outside PSG are good teams, but aren't very close to their Serie A counterparts. Serie A is a league going up. Ligue 1 is a league going down. Juventus is 2nd in Serie A as of now, but would lead Ligue 1 by 6+ points with ease.