My husband and I gave a real estate to our daughter with stipulation of a right of return. My husband died in March 2015 and my daughter in November 2016. Now the notaire in charge of the estate of my daughter only gives the right to return [...]

[...] only half of the property. Is this normal?

Yes, because enforcement of the right of return only plays if the donee (in this case your daughter) dies before the donor (here your husband). Your daughter having died after her father, but before you, the right of return applies only to your profit and up to what you gave her (half of the property).