All he'd have to do is be smart enough to keep his mouth shut when he saw Mathilde.
Lol, I imagine the scene.
"Mathilde, is that y woops!"
"Darth Vader is
scary and I
The God
father"

you've reminded me that I need to watch
Army of Shadows
again soon.
I'm proud to say my poetry is only understood by that minority which is aware.

"I think the plan they ended up using didn't require that Felix be notified, and that Jean Francois was shown to have acted foolishly in choosing to do things independently."
This is correct. It was not a plot hole. The plan they ended up using did not require Felix to be informed. He would've been transferred by the doctor from the cell to the car. There was no need for Felix to be informed to be in a certain place at a certain time nor to be prepared to run/fight or anything like that. All he'd have to do is be smart enough to keep his mouth shut when he saw Mathilde.

I think the plan they ended up using didn't require that Felix be notified, and that Jean Francois was shown to have acted foolishly in choosing to do things independently.
Baseball lies to us seductively, and we know we're being seduced, and we don't complain.

Yes it is a big plot hole.

I think that is in fact a plot hole. Jean Francois wanted to solve Mathilde's problem by turning himself in and informing Felix of the plan, but he left with the impression that he had deserted, so how could have Mathilde known that Felix had already been informed?
And why did he write Mr DUPONT in that anonymous letter?

I agree with most of your points; but I was a bit disappointed in how this plot point was handled. Since the plans hadn't been formed yet, etc.; what could have possibly told Felix, especially since no one knew what he was doing. Not to mention that it is a bit contrived to assume that he would end up in the same cell (which was described as specially reserved for high-quality prisoners who knew a lot about the Resistance. J-F was only a low-level guy who had been anonymously denounced as far as the Gestapo knew).

That was my read as well but I just wasn't sure. Thanks!

Yes, J-F is turning himself in when he constructs that letter from the newspaper clippings.
No, nobody else in the group knew he was doing that.
As for the "Why?" .
Think back to the scene before that, when the group (well, mostly Mathilde and Gerbier) were discussing plans to break Felix out. Mathilde says that they would need to get word to Felix somehow, so that he would be prepared. She also said that this was the one element that she still had no idea how to accomplish. (Which may be why she eventually came up with a plan that did not require prior communication with Felix.)
Getting himself arrested was J-F's solution to the problem of getting word of a pending breakout attempt through to Felix. The "dessertion" letter to Gerbier et al was a ploy to cover up what he was doing. He knew that the others would never allow him to give himself up that way (for multiple reasons).