What happened
After Paul Reynaud resigned amid France's military collapse, Philippe Petain became head of government under the French Third Republic.
Why it matters
Petain's accession mattered because it marked the political victory of those arguing that France should stop fighting and seek terms from Germany rather than continue the war from overseas. It is one of the clearest immediate precursors to the armistice of 22 June 1940.
Notes
France was still the French Third Republic at this point, not a monarchy. The office was commonly treated as prime minister, though the formal republican title was President of the Council of Ministers.