This is a circulating copy of an accepted paper: Download Gautret P et al. hydroxychloroquine COVID-ACCEPTED. The only bad news here is that the drug is hard to come by in the U.S. and probably in other countries not regularly afflicted by malaria (not entirely surprising, but it better get rectified!). Drug manufacturer Bayer is "donating" some (all?) of its stockpile to the U.S. government. Here's yet another reason to "flatten the curve" short-term: more treatments (if not cures) are likely to become available as we learn more over time.
(Thanks to David Ozonoff for the pointer.)