In the answer to question no. 113548, we explained the ruling on wearing wigs, and stated that it comes under the heading of wearing hair extensions, which is prohibited.
As for the head covering that is worn by lawyers in some countries, that looks like a wig, it does not come under the same heading for several reasons:
1. Even though this head covering is called a wig, it is not really a wig in shape, colour or the way it is worn, so it is not included with hair extensions, which are prohibited.
2. It is not usually worn for the purpose of adornment; rather it is a professional tradition and convention.
3. It does not involve any element of deceit, so it is more akin to a head covering.
It remains to note that Muslims are obliged to keep away from the traditions of the disbelievers with regard to such clothing, unless it is something that is widespread and commonly done among the people who practice this profession, both Muslims and disbelievers, or it has become compulsory, so that the lawyer cannot appear in court without adhering to this custom.
Please see the answer to question no. 112144 for information on the ruling on working as a lawyer in countries that are governed by man-made laws.
And Allah knows best.