https://gloria.tv/article/wbLdQ4ULJYvj3tbshrhr4tdVS

Original French source
http://medias-catholique.info/rome-les-effets-decisifs-de-la-lettre-des-doyens-et-des-communautes-amies/8711

"On 27 June, Cardinal Müller finally gave Msgr. Fellay the unacceptable conditions required for the granting of the personal prelature , conditions validated by Pope Francis: recognition of the Second Vatican Council, the legitimacy of the Mass of Paul VI, and Profession of faith of Paul VI."

At Saint Nicolas du Chardonnet in Paris, before the sermon, the priest announced that Rome had made 3 unacceptable demands of the SSPX and the SSPX have refused them.

Reading between the lines, it seems that the letter by the 7 Deans of France showed Rome that not all the SSPX would follow Bishop Fellay. Rome realized negociations with Bishop Fellay were pointless as he doesn't have the natural authority to lead the entire congregation.

According to this article http://www.medias-presse.info/rome-les-effets-decisifs-de-la-lettre-des-doyens-et-des-communautes-amies/76438/, on the 8th of May, Cardinal Müller et de Mgr Pozzo had seen a copy of the letter by the 7 Deans. Unbeknownst to the 7 Deans, in Rome The Congregation for the Doctrine of the Faith was to meet on the 10th of May to discuss the Lefebvriste issue. This may have been where they decided to make a proposal to the SSPX that they were bound to refuse, even if quite honestly, it differs little from the April 2012 declaration already acceptable to Menzingen.