As you'd expect from an Irish pub located in the 7th arrondissement, the clientele is well-dressed and relatively well mannered. Frequented by a mix of expats, neighborhood locals and students from the nearby American University, if you hit it on a good night O'Brien's can be a great place to spend the evening. Happy Hour is weekdays 5pm - 8pm and the Sunday night quiz which matches up teams of trivia experts, is also well attended. Free Wifi internet is available.