Born Alexandre Éric Stéphane Tossoukpé in Paris, France on 24 August 2003, Alexandre Éric Stéphane Coste is the son of Prince Albert of Monaco and Nicole Coste, which makes him the younger half-brother of Jazmin Grace Grimaldi. He also has two older half-brothers who live with their father, Nicole's ex-husband, in South America. He is also the step-son of Princess Charlene of Monaco, and nephew of Princess Caroline & Princess Stephanie of Monaco, Countess of Polinac. His mother Nicole changed their surname to Coste on 10 November 2004, a move in which is believe to be in homage to Prince Albert's lawyer, Thierry La Coste.
His mother owns a villa just outside of Monaco in Villefranche-sur-Mer, France and has an apartment in Paris. It is believed that one of these is their primary residence and that Alexandre attends school in either Paris or Villefranche-sur-Mer. At present, Alexandre should be preparing to enter 9ème, this is equal to the 3rd grade in the US system.
Like his elder sister's mother, his own mother fought for years for Prince Albert to publicly acknowledged him as his own. However, Nicole had much more success than Tamara in that department-Prince Albert publicly acknowledged his son in 2005, nearly a year before his sister was acknowledged, and after only about 22 months of fighting it. Also like his sister, he is rarely seen, the last photos of him were around 2009.
In October 2006, his father was interviewed by Larry King, in which he stated his children would not be in line for the Monegasque throne but that they would be taken care of financially. They are also an heir to Prince Albert's personal fortune, estimated at more than one billion dollars. Due to the accession of Monaco to the Council of Europe on 5 October 2004, the European Convention on Human Rights regulates inheritance rights, in addition to the laws of Monaco, which also guarantees familial inheritance for children born out of wedlock.