Détente (pronounced "day-TAHNT") is not really an allusion, but a French term. It is most often used about relationships between nations. It has to do with the relaxing of tensions between formerly hostile groups. What I think is significant about the concept is that while tensions are relaxed, the parties remain very separate.
I encountered this word in a book about overcoming church conflict called Making Peace. They used the term to describe a negative example where two parties disagree, then reach a solution that involves less waves on the surface but no reconciliation between disagreeing parties.
This term was used a lot in the last hundred years about the relationship between the US and the Soviet Union. We weren't dropping bombs on each other, but we were training our children in school what to do in case the Commies attacked. We signed treaties which would limit the expansion of nuclear programs to peaceful use, however much of our intent was more centered around preventing the spread of weapons to other smaller, turbulent nations, rather than on limiting the superpowers from doing what we pleased.
Similarly, there are quite a few examples I could use about how congregations will have, more or less, two congregations meeting in one building at different times because of a disagreement; usually about worship. There might not be open conflict, but there may still be distrust between groups. This is an example of détente; where there is not fighting, but there really isn't real peace either.
Détente means that we sleep with one eye open. Things are calmer on the surface than they might have been, but we're not taking any combative options off the table. While it may seem necessary for international relations, it is not a desirable practice in churches, when genuine peace is possible and divisions can be dissolved. Real peace is not easy, but it is to be desired over détente.