The ceremony was held inside the Big Easy's Contemporary Arts Center, according to ABC News local affiliate WGNO.
Mel Barlow, who photographed the wedding for the couple, posted one snap from the event on Instagram.
Although the guest list was under wraps, celebrities such as actress Nicole Ari Parker and model Selita Ebanks were spotted arriving to the venue in the city's Warehouse District.
Williams, 36, and Ohanian, 34, became engaged last December with the tech enthusiast announcing the news on Facebook.
Four months later, Williams revealed they were expecting their first child, a daughter named Alexis Olympia Ohanian Jr., whom they welcomed in September.