I am not sure if this is going to be part of the Jefferson Apartments at Market Place project. In earlier plans for the Addision Square project, which fell through, this small parcel was supposed to be part of the larger project. Nothing recent has happened along 7th.
Update- Thanks to a commenter it seems it is a separate project by Capital City Real Estate.
This is Capital City Real Estate's project going up at 751 P Street. It will feature 12 condo units. The project website is here: http://www.capcityre.com/751-p-street-nw