I have taken an AF flight from EWR maaaany years ago. Operated on A330. It operated from the DL concourse, and we used the DL lounge, which I confirm isn't great.

PS I remember that flight vividly because the seat next to me was empty when doors closed, and then suddenly an FA placed a friend/family member next to me. Those were the NEV3 days, so having someone next to me did make a difference in space/privacy (it shows how such one-time bad customer treatments stick in people's memory, and how much it would take to make up for that).