I Missed the First Twelve Minutes

I don't know, but according to Wikipedia, the plot starts as follows:

At the end of the eighteenth century, Marianne, a young painter, is teaching painting lessons. One of her students asks her about a painting of hers, which Marianne calls "Portrait of a Lady on Fire".

Years prior, Marianne arrives on an isolated island in Brittany. She had been commissioned to paint a portrait of a young woman named Héloïse, who is to be married off to a Milanese nobleman. Marianne is informed that Héloïse has previously refused to pose for portraits as she does not want to be married. Marianne acts as Héloïse's hired companion to be able to paint her in secret, and accompanies her on daily walks to memorize Héloïse's features.

The first scene is the main character posing for her students. We see the students painting her in pose, as the camera slowly shows us each student's attempts. During the scene, Marianne tells everyone to make mention of the posture, the facial expression, the hands, etc. Then, she asks, in a rather blunt tone, who took out the picture behind one of the students. One of the girls admits to it, and states that she thought it looked sad, and then asked who it was.

Marianne, with some emotional undertone, says that it was someone she knew, and the next scene is her on a boat. We understand she is sailing to the island. We see the ride is rather turbulent, and she is holding on to her painting tools. As the boat is rather small, the waves are tilting the boat back and forth. Suddenly we see the camera pan to one of her tool boxes in the ocean. She then dives into the water to retrieve them.

The next scene is her on the island arriving to the house. She introduces herself, meets the maid, then is shown her room where she undresses and warms up in the nude next to the fireplace.