here's an excerpt from the Wiki page...go to the citations if you have any question about why M. Montagnier was not thought highly of...
"In 2017, 106 academic scientists wrote an open letter "calling [Montagnier] to order". The letter read: "We, academics of medicine, cannot accept that one of our peers is using his Nobel prize [status] to spread dangerous health messages outside of his field of knowledge."[45]
For his defense of such anti-scientific views, Montagnier has been cited as an example of the phenomenon called Nobel disease.[46][47]"
Link: https://en.wikipedia.org/wiki/Luc_Montagnier