Some more info about Princess Antoinette's children from Answer's.com:
Baron Christian de Massy, eldest son of Princess Antoinette and nephew of Prince Rainer III
(Source:Worldroots)
His children:
- Baron Brice de Massy, eldest son of Baron Christian de Massy
- Baron Antoine de Massy, younger son of Baron Christian de Massy
- Baroness Laetizia de Massy, daughter of Baron Christian de Massy
Baroness Elisabeth-Anne de Massy, daughter of Princess Antoinette and niece of Prince Rainer III
(Source:Worldroots)
Her children:
- Jean-Léonard Taubert Natta, son of Baroness Elisabeth-Anne de Massy
- Mélanie de Lusignan, daughter of Baroness Elisabeth-Anne de Massy
- Keith Sebastian Knecht, son of the late Baroness Christine de Massy
A little more about Elisabeth-Anne:
Elisabeth-Anne, Baroness de Massy was born on 13th January 1947 to Princess Antoinette of Monaco and her lover Aleco Noghes. She is a first cousin of the reigning Prince Albert II and niece of Rainier III. She is the godmother of Princess Stéphanie of Monaco.
She was the eldest of three siblings; the others were Christian Louis (born 1949) and Christine Alix (1951–1989).
She was married to Bernard Taubert-Natta, a Swiss Baron in 1974 and has one son Jean-Leonard Taubert-Natta. Her second marriage to Nicolai de Lusignan produced a daughter Melanie in 1985.
She is well known for her charity work in Monaco.
She lost her place in the line of succession to the Monegasque Throne with the death of Rainier III.