The old town is ringed by the river and canal system which makes it very easy to walk around and explore. You'll find narrow winding lanes and hidden waterways, along with Renaissance mansions and a Medieval tower, the Tour d'Argent. This tower was originally built as a defence keep in the 13th century, and has since had many uses, including a cinema and theatre during the last century. There are now plans to restore it completely and use it as a culture space.
One way or another you'll end up at the central square which is home to the old granary, now the tourist office, and a rather impressive church, the Collegiale Notre Dame des Anges. This Baroque styled church may look rather austere from the outside, but the interior is more lavishly decorated with grand paintings, murals, sculpture and of course, 222 angel statues who accompany the Virgin to heaven. The tourist office offers guided walks and tours if you'd like to find out a bit more about the history of L'Isle sur la Sorgue.
The Campredon Art Centre is an 18th century mansion that shows contemporary art exhibitions throughout the year (closed on Sundays July - September, and Mondays and Sundays from October - June). There are also two museums - one is an old-fashioned school museum, the other an antique doll and toy museum (only open during the school holidays).
Throughout the town there are art galleries, antique shops and gift shops. Many cafes and restaurants offer terraces overlooking the rivers, making it a fine spot for lunch or dinner.