CORPIQ offers landlords various resources, such as a form providing the option for a refused prospective tenant to pay a security deposit, and this in all legality. CORPIQ recently obtained a favourable decision from the Régie du logement, notably thanks to this form.
Check out these useful links concerning the security deposit
Options of surety offered to the potential tenant Form (members only)
Decision of the Régie du logement concerning the security deposit (2020) (available in French only)
Q&A about the security deposit (available in French only)
State of the premises form (members only)
Court of Quebec decision on surety bonds (2020) (available in French only)