As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FORWARD LAV SMOKE DETECTOR ACTIVATED IMMEDIATELY AFTER TAKEOFF AND THE LEAD FLIGHT ATTENDANT OBSERVED SMOKE IN THE CABIN. FLIGHT RETURNED TO MSP AND LANDED SAFELY. MAINTENANCE REMOVED, INSPECTED AND REINSTALLED THE LAV SMOKE DETECTOR. THERE WAS NO EVIDENCE OF SMOKE OR OTHER DAMAGE NOTED IN THE LAV OR ANY ADJACENT AREAS. TESTS ALL CHECKED NORMAL. AIRCRAFT RETURNED TO SERVICE.