My widowed mother passed away 15 years ago, and my brother and I never went to a notary to settle her estate. We want to sell her house, but a friend told me that we no longer have the authority to do so. Is this true?

Yes. Upon a person’s death, their heirs have 10 years to declare whether they accept or reject the estate (Article 780, paragraph 1 of the Civil Code). After this period, they are considered to have renounced the estate (Article 780, paragraph 2 of the Civil Code) and therefore no longer have any rights to the deceased’s property (Article 805, paragraph 1 of the Civil Code).