I would like to address a comment made in a locked thread which argued that the sovereign family's House Laws are unconstitutional and therefore invalid because they are not included in the Constitution itself. (More specifically, the comment argued that the rule in Article 24 of the House Law, which excludes any person who marries without the Sovereign Prince's consent from succeeding to the Monegasque throne, is unconstitutional and invalid.)
This is not the case; the House Laws are constitutional. The Constitution not only refers to the House Laws four times, but the Constitution explicitly gives the House Laws the authority to establish rules for the succession to the throne, regencies, and the crown properties.
The current constitution of Monaco:
https://www.gouv.mc/Gouvernement-et-Institutions/Les-Institutions/La-Constitution-de-la-Principaute
An English translation:
https://en.gouv.mc/Government-Institutions/Institutions/Constitution-of-the-Principality
Quoting the Constitution:
Art. 10. (amended by Law n°1.249 of April 2nd, 2002) - The succession to the Throne, opened by death or abdication takes place by the direct and legitimate issue of the reigning prince, by order of primogeniture with priority given to males within the same degree of kinship.
In the absence of direct legitimate issue. the succession passes to the brothers and sisters of the reigning prince and their direct legitimate descendants, by order of primogeniture with priority given to males within the same degree of kinship.
If the heir, who would have acceded by virtue of the preceding paragraphs is deceased or renounced the Throne before the succession became open, the succession passes to His own direct legitimate descendants by order of primogeniture with priority given to males within the same degree of kinship.
If the application of the preceding paragraphs does not fill the vacancy of the Throne, the succession passes to a collateral heir appointed by the Crown Concil upon same advice of the Regency Council. The powers of the prince are temporarily held by the Regency Council.The Throne can only pass to a person holding Monegasque citizenship on the day the succession opens.
The procedures of application of this article are set, as needed, by the House Laws of the Sovereign Family promulgated by Sovereign ordinance.
Art.11. (amended by Law n°1.249 of April 2nd, 2002) - The Prince can exercise His sovereign powers if He has reached His adult hood fixed at the age of eighteen.
During the Prince's adolescence or in case the Prince is unable to exercise His functions, the organisation and conditions of exercise of the Regency are provided for by the House Laws of the Sovereign Family.
Art. 34. The Crown’s property is submitted to The Sovereignty's exercise.
It is unalienable and imprescriptible.
Its consistency and regime are determined by the House Laws at the Sovereign Family.
Thus, Prince Albert II formulating more detailed succession laws through his House Laws is permissible and legal according to the Constitution.
Furthermore, the Constitution not only acknowledges the House Laws, but it grants them a privileged status in which they are exempted from being debated by the Government:
Art. 46. (amended by Law n°1.249 of April 2nd, 2002) - Sovereign Ordinances, which are excluded from debate in the Government Council and presentation to the Minister of State, pertain to:
- The House Laws of the Sovereign Family and these of its members
- The affairs of the Direction of the Judicial Department
- The appointment of members of the Sovereign Household, the diplomatic and consular corps, the Minister of State, the Government Councillors and assimilated civil servants, the magistrates in the judiciary
- The issue of exequatur to consuls
- The dissolution of the National Council
- The granting of honor titles
Finally, the Sovereign Family has continuously had House Laws, regulating succession, regency, property, marriage, etc., all published in the official Government journal of Monaco, since
at least 1882.
https://journaldemonaco.gouv.mc/Journaux/1882/Journal-1258
From the pragmatic point of view: When no one has challenged the constitutionality of the House Laws in over 141 years, it probably does not have a chance of happening anytime soon.