Many thanks to @joehouston09 who has tweeted that The Whole Truth is filming it’s court scenes at an old school on Bayou Rd. in St. Bernard Parish. He has spotted Keanu Reeves & Renee Zellweger on site.
Update: The old school is the original historic courthouse that dates back to 1915. It served as St. Bernard’s first courthouse until 1939, when the parish seat of government was moved to Chalmette. The building was later leased to the St. Bernard Parish School Board, and has been home to St. Bernard High School, P.G.T. Beauregard High School, and prior to Hurricane Katrina, P.G.T. Beauregard Middle School.
The building has been recently restored and appears to house several local government agencies.
Information from Blog NOLA