Because the diocese of Fréjus-Toulon is too pro-Traditional, of course...
[EWTN] The Vatican is investigating the Diocese of Fréjus-Toulon in France for its adherence to the teachings of the Second Vatican Council and its support of the traditional Latin Mass. The investigation, which will begin on February 13 and be led by Archbishop Antoine Hérouard with the assistance of Bishop Joël Mercier, is part of the Vatican's efforts to ensure that the teachings of the Council are upheld across the Catholic Church.
A communiqué from the Apostolic Nunciature of France, published by the Diocese on its website, states that the apostolic visitation is "by mandate of Pope Francis" and comes after "a certain number of difficulties encountered in the diocese."...
Bishop Rey is known for supporting the traditional Latin Mass and has used the 1962 Roman Missal to preside at ordinations. The Fraternity of St. Joseph the Custos, the Monastery of St. Benedict, and the Institute of the Good Shepherd are in his Diocese.
The Benedictines, who celebrate the traditional Latin Mass, ordained several of their members outside France with a bishop whose identity has not been revealed after Bishop Rey could not preside over them because of the scrutiny under which his Diocese was placed.
Following the promulgation of Traditionis Custodes, Pope Francis' 2021 motu proprio restricting the traditional Latin Mass or Tridentine Mass, Bishop Rey highlighted the concerns of several priests and communities in his Diocese.
Will it find problems? But of course: a visitation will find problems in ANY DIOCESE IN THE WORLD. But the choice of dioceses for visitation in this pontificate is clear: if you are traditional, or even just friendly to Tradition, or even merely known as friendly to Tradition, you are the enemy and you must be eliminated.
It's the old Peronist adage: "To the friend, everything; to the enemy, not even justice."