The Catholic church in France is appealing against a verdict recognizing a de-baptism, the first to be recorded there.
The ruling would allow French Christians to have their names officially deleted from baptismal registries.
If the ruling prevails, Deutsche Welle Radio reports it may set a legal precedent and highlight a broader drift from the church in Europe.
There are no official statistics on de-baptism in France, but the number is estimated to be small.
However, falling baptismal numbers are regarded as a greater concern.
Some 90% of children were baptised half a century ago.
Today, the number is one in three.