I'm retired and currently live in France. I have a French bank account (and a US one too). In Sep 2019 I will be visiting Bucharest and Brasov in Romania. I'm curious as to the best places to exchange either USD or Euros for the Romanian Leu.
By withdrawing from a bank-operated ATM from your own account.
You will pay a premium for physically exchanging cash. Do you have any concerns about simply withdrawing local currency from an ATM machine?
Any reason why you wouldn't use your US or French ATM card in a Romanian ATM? That's what I did in 2015.
I don't remember seeing exchange booths in Romania on that trip, but they may exist. I've certainly seen them in some other former Iron Curtain countries.