Background
In 1864 Prince Gaston d’Orleans married Princess Isabella of Brazil, heiress to the Imperial throne of Brazil. Prince Gaston moved to Brazil and took the Brazilian nationality. Thus, the Prince ceased to be a French dynast.
In 1889, the Brazilian monarchy was illegally overthrown in a coup. Prince Gaston then hoped that he might regain his dynastic rights.
Prince Philippe, Count of Paris and Head of the House of France made clear that this was not possible:
Gaston’s eventual claims to reclaim his rank in the house of France and everything that follows from it are absolutely unacceptable. You saw in my letter that I did not even imagine such claims existed. When one leaves the house of France to become a foreigner, when one renounces the life of an exile waiting, hoping and remaining true to France, in order to seek from a foreign throne an official position, such an act has irrevocable consequences. One cannot, thirty years later, say that one made a mistake, that the past doesn’t exist, and claim among us a place one has willfully left. Naturalization in Brazil excluded him from the house of France just as it excluded the uncle Montpensier and his male issue. It is the fundamental law of heredity in the Capetian line which, itself, ascended the throne by virtue of that law. That law must be irrevocable, or else it would be enough for one of those excluded to naturalize himself in order to trump all those who enjoyed in the meantime the rights that devolved to them.
Prince Gaston attempted again in 1902 to restore his rights. The Duke of Orleans, the new Head of the Royal House, once again denied Prince Gaston.
In 1909, the Family Pact was created. The Pact confirmed the removal of the Brazilian branch of the House of Orleans from the French succession [Note: while there is a Brazilian branch of the House of Orleans, there is not a Brazilian branch of the House of France. Such a concept would be antithesis to the Fundamental Laws and everything they stand for].
Misunderstandings
Many people have erroneously assumed that the Family Pact restored the Brazilian Orleans to the line of succession. This is not the case. Another is the idea that the Brazilian Orleans regain their dynastic rights upon the extinction of the other dynasts.
This comes from a misunderstanding of Article 4:
The Comte d’Eu and his sons hereby undertake, solemnly, on their behalf and that of their issue, to press their claims to the crown of France and to the position of head of the house of France, only in the case of total extinction of all the French princely branches that currently form the House of France. We take note of this solemn promise which shall take effect and shall be established by the addition of signatures to this our declaration.
The Pact says the Brazilian Orleans may “press their claims,” but it does not say their claim is automatic or that their dynastic rights would be restored.
To understand this, we must ask ourselves what happens if all dynasts of the House of France were extinguished.
Under this scenario, the Estates-General would elect a new king and establish a new dynasty for France.
It was such an election that established the Capetian Dynasty in the first place, where the French chose the French Hugh Capet over the foreign Charles de Lorraine, who had become a subject of the Holy Roman Emperor.
The Family Pact is simply saying the Brazilian Orleans may press a claim. It would be up to the Estates-General to accept it or not. However, it seems unlikely that the Estates-General would accept it. There are, after all, illegitimate Boubons living in France who would likely be more appealing.
Conclusion
The Family Pact simply confirms the Unionist position that the House of France is not international. A prince who leaves France to become a foreigner forfeits his dynastic rights to the French throne.
A simple reading of the text of the Pact confirms that it is consistent with the Unionist understanding of the Fundamental Laws of France.
The French Unionist Project 