In general, illegal contracts are void.

一般来说，非法的合同是无效的。

youdao

This two-tier labour market divides workers into a privileged groupcocooned from the reality of recession and the disadvantaged ontemporary contracts, in unemployment or in illegal jobs.

这种二重的劳动力市场使得一部分人在市场衰退下得以全身而退，而另一部分主要由临时工，失业人员和非法劳工构成的人却步履艰难。

youdao

According to the rules, the agencies and agents cannot make price difference, provide help in equivocal contracts or provide real estate brokering service to illegal and banned deals.

该《办法》明确，房地产经纪机构和人员不得从事赚取差价、协助签订“阴阳合同”、为不符合交易条件和禁止交易的房屋提供经纪服务等违法违规行为。

youdao

The reason the mafia thrives in countries where it's hard to write legal contracts-- let's say some new parts of the former Soviet Union or some parts of Africa the reason the mafia thrives in those environments, is that it substitutes for the law and enforces both legal and illegal contracts.

黑恶势力在那些,书面协议不受保护国家不断壮大,比如前苏联新成员国 或者非洲,为什么黑恶势力在这些地方发展壮大,因为这是法律强制力的补充,它维系所有合同,不管是不是合法的

耶鲁公开课 - 博弈论课程节选

Downing Street backed firms paying a living wage, but said restricting contracts in this way could be illegal.

BBC: Living wage: Ed Miliband pledge over government contracts

The government said it backed companies paying a living wage and would encourage more businesses to do so, but said restricting government contracts in this way could be illegal.

BBC: Derby City Council to introduce living wage from 2014