France is essentially first-past-the-post with a single runoff for presidential (who is a very powerful executive like US model + he can dissolve parliament).

France is essentially first-past-the-post with a single runoff for presidential (who is a very powerful executive like US model + he can dissolve parliament). The dynamics are same prior to runoff because the plurality electoral system gives no representation to the majority that didn't vote for the winner (almost a given since there will be >2 candidates). You'd need proportional representation and/or an electoral system like Borda,RCV,Star or instant runoff to significantly proof against spoiler mechanics that the wealthy can exploit. Again, none of these measures guarantees against money corrupting electoral processes, just makes it more costly and unsure that any given corruptive effort pays off.