In principle, according to the Judicial Code, only Belgian and EU nationals can use the title of lawyer and practice the profession. The nationality condition is waived with regard to foreigners who have resided in Belgium for six years; or three years if the foreigner is married to a Belgian national or has one or more ascendants or descendants residing in Belgium for at least three years. In addition to the prior residency requirement, the foreign applicant must produce "a certificate issued by the Minister of Foreign Affairs under the terms of which national law or an international convention authorizes reciprocity" in order for the nationality condition to be waived. Locally licensed or EU lawyers can create a commercial entity with other professionals, but the Bar can deny the creation of the entity if all or a part of the capital is owned by, and/or if the decision-making power is exercised by persons who do not have the status of lawyer within the meaning of the provisions of the Judicial Code.
"Art. 428. No one may use the title of lawyer or practice it unless he is Belgian or a national of a member state of the European Union, holder of a doctorate or law degree, if he is has taken the oath referred to in section 429 and is entered on the roll of the Order or on the list of trainees.
The nationality condition may be waived in the cases determined by the King, on the advice (of the French-speaking and German-speaking Bar Association and of the Orde van Vlaamse balies).
[...]
Art. 428bis. Nationals of a member state of the European Union who meet the following conditions may also bear the title of lawyer and practice it:
1 ° hold a diploma, certificate or other title [referred to in Directive 2005/36 / EC of the European Parliament and of the Council of 7 September 2005 on the recognition of professional qualifications], and from which it follows that the holder has professional qualifications to access the profession of lawyer in a Member State of the European Union; [...]
3 ° have passed an aptitude test, organized by (the Order of French-speaking and German-speaking bars or by the Orde van Vlaamse balies, depending on the bar to which he is applying for registration,) when the training he has received bears on subjects which are substantially different from those covered by the Belgian law degree (unless the knowledge which the person concerned has acquired during his professional experience is such as to compensate, in whole or in part, for these substantial differences).
[...]
Art. 477octies. 
§ 1. One or more persons registered on the list of lawyers who practice their profession under the professional title of another member state of the European Union and members of the same group in the member state of origin, may practice their professional activity in Belgium within the framework of a branch or a secondary firm. [...]
§ 2. Two or more persons coming from the same group or from the same member state of origin and registered on the list of lawyers who exercise their profession under the professional title of another member state of the European Union may practice their profession in a group, under the conditions set for lawyers registered on the roll of a Belgian Order.
§ 3. §§ 1 and 2 are also applicable to the joint exercise of the profession in Belgium:
a) between several people working under their original professional title and coming from different Member States;
b) between one or more persons referred to in point a) and one or more lawyers registered on the roll of a Belgian Order.
§ 4. The person wishing to practice under his original professional title informs the bar with which he is applying for registration, in accordance with article 477quinquies, of the fact that he is a member of a group in an original member state and gives all the useful information about this group.
§ 5. By way of derogation from §§ 1 to 4, the Bar Council with which a person is registered or requests registration on the list of lawyers who practice their profession under the professional title of another member state of the European Union, may refuse to practice the profession in Belgium as a member of a group comprising people outside the profession.
The group referred to in paragraph 1 includes people outside the profession if at least one of the following conditions is met:
1 ° the capital of the latter is held in whole or in part by persons who do not have the status of lawyer within the meaning of the provisions of this Code;
2 ° the name under which it operates is used by the persons referred to in 1 °;
3 ° the decision-making power is exercised there, in fact or in law, by the persons referred to in 1 °.
The Bar Council of each arrondissement can also oppose the opening of a branch or a secondary law firm wishing to register on the list of lawyers who practice their profession under the professional title of 'another member state of the European Union if it appears that this group of lawyers includes people from outside the profession, within the meaning of the previous paragraph.[...]" (Judicial Code (1967101053, 31-10-1967), last amended 12-07-2021, Articles 428, 428bis and 477octies [google translation])
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"Article 1. The nationality condition provided for in Article 428, paragraph 1 of the Judicial Code is waived in favor of foreigners: 
1 ° who has established his domicile in Belgium for at least six years on the date of the request registration; 
2 ° which justifies, if it has been registered with a foreign bar, that it has not been omitted for reasons calling into question its private or professional good repute; 
3 ° which produces, except in the case provided for in Article 2, d, a certificate issued by the Minister of Foreign Affairs under the terms of which national law or an international convention authorizes reciprocity; 
4 ° which at the time of the registration request has not kept in foreign country, neither domicile, nor residence within the meaning of article 36 of the Judicial Code, nor registration with a foreign bar, and undertakes not to have one.
Art. 2. The period of domicile provided for in article 1 is reduced to three years for foreigners who meet one of the following conditions: 
a) be the spouse of a Belgian person by birth; 
b) have one or more ascendants or descendants residing in Belgium for at least three years; 
c) be a national of one of the Member States of the European Economic Community; 
d) be recognized as a refugee by application of the convention relating to the status of refugees, signed in Geneva July 28, 1951 and approved by the law of June 26, 1953.[...]" (Royal Decree derogating from the nationality condition provided for in article 428 of the Judicial Code relating to the title and exercise of the profession of lawyer (1970082402, 08-09-1970), entry into force 10-09-1970, Articles 1 and 2 [google translation])
Judicial Code (1967101053, 31-10-1967), last amended 12-07-2021, Articles 428, 428bis and 477octies
Royal Decree derogating from the nationality condition provided for in article 428 of the Judicial Code relating to the title and exercise of the profession of lawyer (1970082402, 08-09-1970), entry into force 10-09-1970, Articles 1 and 2
[<a href="http://www.ejustice.just.fgov.be/eli/loi/1967/10/10/1967101053/justel">Code</a>],[<a href="http://www.ejustice.just.fgov.be/eli/arrete/1970/08/24/1970082402/justel">Decree</a>]