Well, some (Loire 46; MS225 and Dewoitine D371 aka "Flying Coffin") were indeed quite anecdotical.
Others, such as Spad S510 and Dewoitine did fly war missions in the first few weeks. Some D510 even made a few failed interceptions in the Lyon area. Of course, german recon planes were by far faster... And as I said, they were on reserve bases and squadrons, deeper in the Country, not in Lorraine or Alsace as top of the line models.
That being said, I'm in no way asking for them in any future BoF Campaign. They would just make an awesome addition to have the squadrons that used those planes using them in the first missions and then upgrading to newer design during the course of the game. But it's indeed not that necessary.
It shall also be noted that equivalent german models, Heinkel 51 and Arado something were also serving at that time and were phased out in the same time: late 39, early 40.
Regarding the start of the campaign:
Is it possible to have a period of small skimirshes and espaced missions and then suddenly the real show in the same scenario?
Well, if it's the case, 1939 would be great.