Lens seems to be struggling to replicate last season's magic. Despite their strong home form, their season started poorly, and they're not the same team. Against PSG, especially in their current form, is scary for any club. PSG hasnt lost in 13 games and has more depth than Lens. Lens's win over PSG last time was stunning, but repeating it this time seems unlikely. Lens might even consider a draw under the circumstances.
Lens performance this season has been very poor and just like you said they really seem to have been struggling on this season because there efforts are not really impressive, I could remember the last time they meet arsenal on there champions League group and arsenal was able to show them there greatest surprise by giving them 6-0, so perhaps the club really need some adjustments before they come back next season because if they failed to get more good quality players during the transfer window they will not improve on there performance.
However there ongoing match today against PSG really seem challenging for Lens because PSG has been really dominating them and currently PSG has scored Lens 1-0 through penalty and with the way the match is going PSG will score more goals on there second half.