In France, state pays some money to parties with elected members (but given the voting system it's hard to get those).

For donation, only people can give to parties and not corporation (to my knowledge).

Up to 7500 euros per person per year is eligible for tax deduction of 66%, it means that if you pay enough taxes, state will pay you back 0.66*7500 = 4950 euros, so real cost for you of a 7500 euros donation is only 2550 euros.

And I just wrote a 7500 euros check to Segolene Royal campaign association :).