Did Charles de Gaulle contemplate invading Monaco in the 1960s?

De Gaulle was very angry that Monaco was a tax haven and wanted Monaco to collect French income taxes on French citizen's accounts in Monaco's banks. At first, Monaco refused, so De Gaulle closed the French border with Monaco. He also gave a speech in Paris where he promised to "Aphixiate" Monaco. Grace Kelly was very concerned about this situation, and she really thought the French were going to invade her little principality. Eventually, a compromise was worked out that satisfied De Gaulle and no invasion occured. Source "True Grace: the Life and Death of an American Princess" by Wendy Leigh.