I headed back to Google to do more searches on Liebman, Clerc, Neuilly, Arnaud, Gerald, and related terms. Suddenly I was seeing things about Henry Kissinger and the Paris peace talks. Several sites have news archives related to the Vietnam peace negotiations that took place in Paris in 1972 and '73. Clicking through to these articles, we find out that the Liebman/Clerc home in Neuilly was one the places where Kissinger and Vietnamese negotiator Le Duc Tho secretly met.
By the time the house was used for a third meeting, its location was hardly a secret and was well staked out by the international press corps. Arnaud was widely interviewed as the homeowner. Here is an example.