We're going to be driving from CDG to Honfleur on a day that looks to be rainy. Since we can't check into our apartment until late afternoon, but need to pick up our leased car in the mid-morning, we thought a stop at Monet's garden in Giverny would be a good way to break up the drive and kill some time. I'm wondering about parking - and leaving the car with all our luggage in it. I know enough to be sure nothing is visible, but would we be taking too much of a risk in doing this?

I'd risk it

Me too. Haven't done at Giverny, but have parked a car full of stuff, including my trike insde, his bike on the back, all our luggage and electronics, at other places. Parked the bus-camper at such sites too, even fuller of stuff and easier to break into if a thief wanted to.

I agree with Bilboburgler. In my opinion the risk is likely very low (although not zero obviously).

I have done this on several occasions, including in Provence lately (Aix-en-Pvce, Vaison-la-Romaine, Nyons, Grignan, etc.). The usual precautions: keep your passports with you, leave absolutely nothing in sight inside the car, do not access the trunk at all when arriving in the parking lot (if you must retrieve something from it, do it ahead of time well before arriving), whenever possible practice defensive parking. You could also check reviews on TA or others to see if anyone has had issues recently at this particular location.

In the end it essentially boils down to your personal comfort level.

Although you didn’t ask… there are two sites worth the journey right near Giverny. The village of La Roche Guyon and the troglodyte church of the annunciation.

The castle at La Roche Guyon is built up against the side of a cliff with tunnels dug into the cliff. And the church is a small but notable site of unusual architectural merit.

Then there are very impressive ruins along the Seine on the way to Honfleur including the Abbaye of Jumieges and Chateau Gaillard.

I liked all of these sites more than Giverny.

We often have luggage in our car if we visit a site along the way, also on the parking lot near Monet's Garden.