Question juridique clé
Whether the subtenant was in default under the lease despite alleged set-off by submitting an invoice.
Solution extraite
The invoice submission did not amount to a clear declaration of set-off; the rent arrears therefore remained unpaid and default existed.
Motifs extraits
Set-off under Art. 124 para. 1 CO requires an unequivocal declaration to the creditor. A mere invoice, without reference to the allegedly compensating claim, is insufficient.