Shakespeare and Company seems like it might fit in Diagon Alley. 
Founded by an American after World War II, it prides itself on welcoming one and all, (Be Not Inhospitable to Strangers Lest They Be Angels in Disguise, as their website says). They even allow struggling writers to sleep there. Some fifty thousand of them have taken them up on the offer. Barbara and I went twice and I was happy to find a book by an obscure author about whom my son, David, had written his thesis. Nice little souvenir. The first night we were in Paris, we were at the bookstore when it was evacuated, because of the strange behavior of a mentally ill young man. The drama ended up with his injuring himself in front of a poetry reading group that hadn't left the store quickly enough then being taken away in an ambulance.
Founded by an American after World War II, it prides itself on welcoming one and all, (Be Not Inhospitable to Strangers Lest They Be Angels in Disguise, as their website says). They even allow struggling writers to sleep there. Some fifty thousand of them have taken them up on the offer. Barbara and I went twice and I was happy to find a book by an obscure author about whom my son, David, had written his thesis. Nice little souvenir. The first night we were in Paris, we were at the bookstore when it was evacuated, because of the strange behavior of a mentally ill young man. The drama ended up with his injuring himself in front of a poetry reading group that hadn't left the store quickly enough then being taken away in an ambulance. 
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