Shortly after President Trump arrived in France on Friday for an official visit, he took a moment to tell the country’s first lady, Brigitte Macron, what he thought of her physical appearance.

“You’re in such good shape,” Mr. Trump told Mrs. Macron, who was standing in a grand marble hall with her back to a camera that recorded the incident. He then turned to the president of France, Emmanuel Macron, and said, “She’s in such good physical shape.”

“Beautiful,” Mr. Trump said, turning to the first lady of France. She appeared to grab Mr. Trump’s wife, Melania, by the arm and take a step backward. Mrs. Trump stood next to her, smiling.

The encounter happened during a tour of the Hôtel National des Invalides, a museum complex in central Paris that houses the tomb of Napoleon Bonaparte. It was broadcast live on a Facebook video stream on Mr. Macron’s official Facebook account. A clip of the episode soon spread widely online and in the news media.