B757-200
Flight Crew Air Transport Pilot (ATP)
Confusion; Communication Breakdown; Situational Awareness
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Ground Incursion Runway
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Procedure; Human Factors; Weather
We deiced and taxied to Runway 33 as per ATC instructions. Departure Runway was 33 and Arrival Runway 15. ATC issued 'Company Line up and Takeoff Runway 33'. Clearance was read back correctly. I had heard a couple landing clearances given to other aircraft to land Runway 15 during deice and taxi to runway. Upon lining up on Runway 33; I observed what appeared to be another aircraft rolling out on Runway 15. Discussed with First Officer that I think there is an aircraft on the runway. He agreed. We queried Tower about an aircraft still on runway. Tower hesitated with communication; [and] then issued 'Abort takeoff' clearance. We had never started takeoff as we observed an unsafe situation. Tower was very apologetic upon issued takeoff clearance mistake.  ATC needs to be particularly aware of all aircraft locations during single runway operations with landings and takeoffs occurring at opposite ends. Especially during low visibility conditions.
A B757 was cleared for takeoff on LFSB Runway 33; but the takeoff clearance was canceled after the crew notified the Tower that traffic was rolling out after landing on Runway 15.