Lens top position is not one I consider a problem even to PSG, even as PSG is jot exactly at the top they will possibly get to the top and win the trophy, I would wish Lens will win and have a different record for the league again after a long stretch of PSG serially winning the title, so we get to see the variety in the league.
I'm not particularly worried about Lens' current top spot because there are still many games left, and the points gap with PSG isn't that big, so a defeat or draw for Lens in the next match could see PSG return to the top of the standings. Unless PSG drops points in the next few games Lens' chances of winning the title will increase, but given the current situation that seems unlikely. People might want to see a new title contender in Ligue 1, but if the strength of the clubs there isn't much better, it will be difficult to break PSG's dominance.