I bought this vintage card on a whim because I collect neither cards from Biarritz (south east France) nor of royalty. It shows King Edward VII of the United Kingdom strolling along "la Grande Plage". It doesn't look much like a beach to me, but that's irrelevant. He apparently took a holiday each year in Biarritz.
The message on the back reads:
"C'est aussi que j'ai vu Sa Majesté le Roi d'Angleterre sur la plage aujourd'hui" [I also saw His Majesty King of England on the beach today]And that I found interesting enough until I saw the date 24.4.10. King Edward VII, or Bertie as he was known to his family, died in 1910 I looked up the dates. He went to Biarritz in March 1910. While he was there, he collapsed and stayed on longer than originally intended, not returning until 27 April 1910.
So he was spotted by the writer of this card just days before his return to London. He died just 9 days later on 6 May 1910.