With a timeshare you don't actually own anything. You are simply paying for the right to access a resort one or two weeks a year.
With a French Leaseback you physically own the property. It's your asset. You can continue to lease the property to the management company, or after the lease has expired you can rent out the property yourself, stay in it, or sell it. Essentially this is a buy to let property, where all management is done for you. That's very different to simply buying 'time'.