PSG's move to focus more on the Champions League is very appropriate because in Ligue 1 no team has been able to surpass PSG until this season and Brest itself will also be quite overwhelmed when having to face a team like PSG who in general have been much more consistent in playing in Ligue 1 this season. In addition, the next match for PSG is to be the home team with Brest as their guest and that certainly will not make PSG afraid because PSG is always better when playing at home with any opponent in Ligue 1.
PSG have been focusing on the Champions League games for the last few years, because they don't have enough competition in Ligue 1 to put more effort into it than they do. And PSG rarely had any problems in the group stage, the main difficulty starts at the playoff stage. I think Enrique will play to win against Brest, because they don't have such a big advantage over their opponents in Ligue 1, PSG will most likely try to score a few quick goals and then calmly bring this match to victory.