17. If there is a limit on the amount a donor can contribute to a political party during an election, what is the limit?

Poland
1. The total sum of natural person's contributions to the Election Fund of a given political party in one year may not exceed 15 times the minimum wage, determined on the basis of separate provisions, in force on the day preceding the payment.
2. If there are more than one national elections or referenda in a given calendar year, the total sums of payments to the Election Fund, referred to in para. 1 are increased to 25 times the minimum wage, determined on the basis of separate provisions, in force on the day preceding the payment. The provision of the first sentence does not apply to by-elections to the Senate and by-elections, re-elections, early elections and new elections to constitutive bodies of local government units falling during the term of office.
Source: Article 36a.1-2, Law on Political Parties,1997 (consolidated text 2018)
The maximum donation for the Election Fund of given political party is 15 times the minimum wage (PLN 39,000 in 2020 - approx. EUR 9,000). from Polish citizens having permanent residence in the Republic of Poland per year. If there are more than one national elections or referenda in a given calendar year, the maximum donation for the Election Fund is increased to 25 times the minimum wage(PLN 65,000 in 2020 - approx. EUR 15,000).
Donations from the same person to many Election Funds are allowed.