Of course the big difference between the historical France/Germany rivaly and a possible future one is France having an independent nuclear weapons capability. Even the UK relies on the US for maintaining - and if rumours are true, being allowed to use - their nuclear weapons. If the EU were to collapse I could see a lot of smaller powers ally with France, under terms very favourable to France, if it meant an ironclad nuclear-response security alliance with France.
Of course the big difference between the historical France/Germany rivaly and a possible future one is France having an independent nuclear weapons capability. Even the UK relies on the US for maintaining - and if rumours are true, being allowed to use - their nuclear weapons. If the EU were to collapse I could see a lot of smaller powers ally with France, under terms very favourable to France, if it meant an ironclad nuclear-response security alliance with France.