Poincaré was hardly a Socialist.
Yes, France was technically a Social Democracy and Socialism was technically part of France's government. But there's a distinction between hard-line communism and regular socialism. Social Democracy may be discredited as a result of Germany's success and full communism may be supported. Robespierre was more of a socialist than Poincare ever was. And considering the French Revolution did bring forth a communist government, it's likely that hard-line communism may be the radical change France undergoes. A second French revolution, if you will.
Can it be that i seeing this too much from a German perspective ?
After all I'm a German...
Back to topic
A Communist France would give interesting implication, if on other side Russia* become also Communist nation, * not USSR we know it's missing Poland, Ukraine and the Baltic states. (one of goal the German military wanted to reach with this War)
A alliance between Communist France and Russia with objective to Attack German Empire would be logical, but depends who is be in charge in Moscow and Paris
i can imagine that Communist France would intervene in secret in Spanish civil war (1936 to 1939)
Here the French support the Communist, while German Empire and Fascist Italy support the Nationalist