how would France be changed if after the fall of the Second French Empire, Henri, comte de Chambord was made Henry V King and the Third Republic never was? would Henry have lasted as king? and would there be a monarchy in France to this day?
Henri had no heirs and was too old produce one by the 1870s. Furthermore, (IIRC) his support was in the hopes that he would be too weak to make any changes to the republican system. But Henri was probably a reactionary (he refused to change the flag even when it cost him his kingdom), so would try to increase royal power at the expense of the people. He would then find his support dwindling, and upon death I imagine that France would revert back to a republic.
A surviving French monarchy could have great effects on WWII (possibly butterflying it away, but lets not get into that). A French King could say screw the Germans we shall fight on and order the bulk of his military to Algeria. I have my doubts Petain would support the Orleanists and might look to the legitimists to take the vacant throne, as they were more conservative in nature.
Two French Monarchies, the Collaborator Legitimists Bourbon's and the Free Orleanists. This could have a big effect on Charles de Gaulle and his role in the Free French movement as people would look to the Free King and not to de Gaulle for hope.