All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The employee and the employer are both bound by the terms of the contract which is signed between them or by the regulations that are in place in the country where the employee works. Allaah Says (what means): {O you who believe, fulfil your obligations.}[Quran 5:1]. Moreover, the Prophet said: "Muslims should fulfil their conditions." [Abu Daawood].
Therefore, if the work contract or the legislations that are in place in that country state that you are entitled for cash rent allowance, but you are not able to get this right except by using the trickery which you mentioned, then there is no harm to conclude the contract which you described. However, if the regulations that are in place do not give you the right of cash rent allowance, but just gives you the right to have a house where you live, then you are not allowed to undertake the ways of trickery which you mentioned. If you do so, you will become among those who cheat and forge documents, and whoever does so is greatly sinful.
Allaah Knows best.