As far as subject of mechanic's lien is concerned, since the subcontractor is usually the practical implementation of contracted work, he should be given the right to claim mechanic's lien by Article 513 of the Civil Code.If the contractor does not pay the subcontractor the remuneration and the subcontractor wants to foreclose in the future, the subcontractor is obliged to ”provide a notice to inform the proprietor immediately” to make the proprietor aware that ”the contractor does not pay the subcontractor the remuneration, and the subcontractor may foreclose the estate of the proprietor which the hire of work is done on.” After the subcontractor informs the proprietor, the proprietor may deduct the unpaid amount of the remuneration when he pays the contractor the remuneration so that he can avoid the danger of double payment.When the contractor demands the remuneration from the proprietor, he should ”demonstrate that each subcontractor has been paid” or ”give to the proprietor a signed release of lien from each subcontractor.” According to the release, the proprietor can be exempted from the subcontractor claiming his lien. This is a way to make the proprietor from the danger of double payment.