Key legal question
Whether the lease became effective despite the unmet suspensive condition or was later validly amended by conduct.
Extracted holding
The lease did not become effective because the suspensive condition was undisputedly not fulfilled, and no clear waiver of the written-form requirement or condition was shown.
Extracted reasoning
The landlord's statements and the acceptance of some payments did not amount to a clear, unequivocal agreement to dispense with the condition; the landlord consistently denied being bound.