Rates would of been seen in June as it was only the last few days. FR have been selling lots of cheap seats like 9.99 ones and that's bound to get bums on seats. Given the very competitive fares to LON from DUB I don't see such a short flight been worth a trip than perhaps to somewhere in Spain.
FR had just under 45,500 seats for June while EZY should have more (?) as they carry around 40,000 so either have excellent LF and both are holding or one is losing a little.