The question around the regulations for indoor commercial flights with UAVs and if SFOCs apply is an often asked question and one that previously was a grey area.
Under the new SI 623-001 document this has been further defined and clarified:
6.16 Indoor Operations
(1) The following TC policies apply when operating a UAV inside a building/structure or in a subterranean environment:
(a) Where only the UAV crew is present an SFOC is not required.
(b) Where only the UAV crew and people directly participating in the UAV operation are present (e.g. actors on a movie set) and no spectators or invited assembly of persons are present, an SFOC is not required. The UAV operator should ensure that all those participating in the operation are briefed on any potential hazards or risks.
(c) Where there are people within the structure who are not part of the UAV operation (e.g. spectators at a sporting event, participants at trade show demonstrations, etc.) an SFOC is required. The Certificate applicant should refer to the appropriate SFOC application process in this SI for further guidance.
(2) In all the above situations, the UAV operator shall gain consent of the land/property owner prior to any such operation.
Basically if spectators are present, people not directly involved in the shoot/event, then an SFOC is needed, otherwise you can operate with no SFOC for indoor flights.