I read the entire thread several times and all I can say is that I understand Haui's desperation to organize to the point of concessions. However, there is no need for concessions in that case(the french case or the german either) because there is popular support for anti war sentiment(the students rally in Germany is one example of that).
If we go back to the post and translate the protest signs that the people were showing, we can find the following. Taking into account your comments Penguin on the organizers, this will allow us to determine if the protest is completely reactionary or genuinely progressive with opportunist rightoids leading it(if you want example of opportunist leading popular demands from the people to divert it back into capitalist, let me know and I can share some).

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Translation of the above: "WE WILL NOT DIE FOR UKRAINE!"
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"NON a la 3e guerre mondiale" -> No to the Third world war.
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Pour la Paix -> For Peace
Most of the messaging and demands(written a few above), from my point of view, are actually progressive and lead to the weakening of the imperialist NATO and EU. Your mistake here will be to dismiss all of the people attending as reactionary just because they were lead by opportunists. Dismissing all of the people makes you dismiss the potential to lead the same people or even a bigger crowd without the opportunist and under an entirely new organization.
We are in dire need of mobilizing every aspect of society. We are in dire need of fostering solidarity in our country.
As learned by the recent Chile experience, fascism doesn’t enter solely through propaganda, it also enters through the open door of demobilization.
As learned by the American experience with Hands off Venezuela rally and Anna Novikova's SOS Donbas, we can foster great movements if we take our chances. The masses can genuinely surprise us if we give them the chance.
Take care.