How can I find a bank account that was opened for me as a minor from abroad.

Not too long ago I turned 18, since then I've gained access to two bank savings accounts opened in my name by my parents or guardians.

However I am told there is another which was opened for the by a relative, unfortunately I no longer have any contact with that side of the family, and I would like to avoid it.

So assuming this account exists, and is in my name, I would legally have access to it now, as long as I can prove my identity as being the one the account is for, yes?

Problem is, I don't know anything about this account, only the city the bank would probably be in.

How could I find out more about this and hopefully gain access to it? I have not lived in Germany since I was born, although my citizenship is German I now live permanently in Ireland.

Thank you for reading and any comments will be appreciated