.. their favour, they allow the nazis to reocuppy Rhineland, but as soon it seems that the dust is settled they deliver a immediate declaration of war and strike on the whole German border ...
A complicated and unnecessary way to do this. In 1923 France & Belgium had invoked clauses in the Treaty of Versailles and each sent a occupation force into the Ruhr region. No DoW was made. Although the ToV had been abrogated by the new nazi government it technically still existed. The French government did consider using this a justification for opposing the German infantry battalions headed west. Aside from internal political divisions the cabinet was told the Army was unprepared to do this. Gamelin, recently appointed, told the cabinet the peacetime organization of the French army prevent the mobilization of rapid response force. He painted a picture of the requirement for a 'full' mobilization of the ground forces, that the peace time training organization was not at all capable of any actual offensive combat operations & implied the mobilization of close one million reservists would be needed to field a army capable of chasing six infantry regiments out of the Rhineland. The government was for fairly obvious reasons unable to face this. Some subsequent historians have made a case Gamelin was dissembling in all this, or perhaps outright lying. I'll leave others to pick at that.
Externally France had little immediate support. Cooperation between Belgium and France on 'Germany Policy' had run aground several years earlier & France could no longer expect the same enthusiastic support that it had in 1923. Britains position was even worse than in 1924 & actual opposition might be expected at the start. Ditto for Italy, the US, and others. What Polands position might be in the immediate moment I cant say. The bottom line is the French government could not count on and international support at the very start of this, other than perhaps Poland.
In retrospect we know there were many weak assumptions here & bad information with the Cabinet. Poor advice from Gamelin has been referred to. While Gamelin was correct in that the French army was configured for training operations and could not deploy a field army, a show of force by those training formations was not impossible. Gamelins negative advice was based on the implication the Germans would fight and a full on battle occur. Post 1945 we have learned Hitler had zero interest in making a fight of it. His directive was for the German soldiers to withdraw wherever confronted by foreign soldiers entering the Rhineland. In that context a few regiments of horse cavalry and armored car squadrons would have sufficed for the French.
For the international setting things were not the same as in 1923/24. The US had a entirely new government, which was hostile to Germanys new facist leadership. When Hitler announced in 1934 the cessation of reparations payments required by the ToV Roosevelt took this further disruption of the global banking system seriously. Not only was the cessation of US obligations under the 1929 Dawes Plan recognized, but the US government ceased any other support or encouragement of loans from the US banks to the German government & business. A outright banking embargo or other effective sanctions were out of the question then, but with the French taking effective action against the Rhineland occupation Roosevelt would have at least threatened the nazi government with financial sanctions. Mussolini was no friend of Germany at this point & Italian policy was still for a independent Austria. decisive French action may have over the longer haul brought the Italians around as well, at least diplomatically supporting the French counter action. Ditto for Belgium. The point here being nothing was set in stone, and the nazi government was starting to be seen as 'different' from the previous post 1918 German governments.