I think he meant something like this “ of the spring months, May crowds can be a problem during holiday weekends “.
I can’t think of many “events “ at this time. Festivals begin in summer. There are visitors but nothing like July and August.
He’s referring to the holidays in May. However, in 2025, the 1st, 8th, 29th holidays all fall on Sundays in 2025, so people won’t be given a bonus day and the long weekends are out for most people. I predict a lot of grumbling because the May long weekends are a much anticipated part of life here. Holidays are fixed to a date or lunar calendar in France unlike the US. May could be slow this year, unfortunately, for businesses that rely on visitors.
FYI: To me, late April is wonderful. The mountain are green and flowers are in bloom, shops and activities are open for the season,.
One caveat is the French school spring vacations that are l spread out by zone from April 5 to May 5. The Paris zone is on vacation from April 12-28 and some are heading south. But the south isn’t on vacation those two weeks, except Montpellier and Toulouse in Occitanie, so all should be functioning in Provence.