7. I rent a flat with a balcony which is found to be an unauthorized building work. Later the landlord removed the balcony. Can I terminate the tenancy agreement?

7. I rent a flat with a balcony which is found to be an unauthorized building work. Later the landlord removed the balcony. Can I terminate the tenancy agreement?

Not every breach of the tenancy agreement would entitle the innocent party to terminate the tenancy early.  Whether the tenant in this example can terminate the tenancy agreement depends on whether the removal of the balcony was serious enough to constitute a repudiatory breach of the agreement on the part of the landlord so as to allow the tenant to elect to accept the repudiation and terminate the tenancy.

The landlord expressly or impliedly covenants not to derogate from its grant.  That means the landlord cannot do any act so as to defeat the purpose for which the lease was granted to the tenant.

Each case must turn on its own facts.  It is very unlikely though the flat was rented for the main purpose of using the balcony.  The occupation and use of the flat should remain largely unaffected.  In the circumstances, it seems unlikely that the landlord has breached its covenant not to derogate from the grant so as to entitle the tenant to terminate the tenancy agreement.