It's frustrating experience for all of us that are interested in the DLC, so here's the facts in easy-to-digest, bite-sized chunks:
Presumably, this is why BioWare's Chris Priestly took the opportunity to clear the air, especially as he claimed some leaked information was fake without actually saying what was fake. Since the Citadel DLC was released there's been all kinds of misinformation and claims of fake information flying around. Hardcore fans of Mass Effect 3 have known about the potential Citadel DLC for months now, as the information was datamined and released to the Internet, but nothing was ever confirmed.