I was wondering if it is possible to transfer money electronically between my Finnish Nordea every-day bank account and my French Societe Generale bank account without any fee? I did a test transfer yesterday and successively sent €1 to the French account and there doesn't appear to be any fees but I am worried in case there is one for larger amounts. In any case, are they usually upfront about any fees?
This is guaranteed to work exactly the same as domestic transfers.
The Single Euro Payment Area (SEPA) makes all payments in euros in and between participating states (all of EU, EFTA, the UK, and some others) exactly the same. One of the main goals of SEPA is:
Only one bank account needed for the whole euro area
The following bit from the SEPA FAQ linked above also pretty much answers your entire question:
SEPA guarantees that your euro payments are made promptly and in full. Your payment shall be received within a guaranteed time, and banks are not be allowed to make any deductions of the amount transferred.
Basically, the applicable EU legislation prohibits any discrimination between payments in EUR based on the origin or destination:
Charges levied by a payment service provider on a payment service user in respect of cross-border payments shall be the same as the charges levied by that payment service provider on payment service users for corresponding national payments of the same value and in the same currency.
An EUR transfer between two accounts in Finland thus has to be handled exactly the same (and with the same fees) as a transfer between Finland and France, so if domestic transfers are free for you, international SEPA transfers have to be, too.