diff --git a/milli/src/search/facet/facet_distribution_iter.rs b/milli/src/search/facet/facet_distribution_iter.rs
index 0c37906ef..722a30e6d 100644
--- a/milli/src/search/facet/facet_distribution_iter.rs
+++ b/milli/src/search/facet/facet_distribution_iter.rs
@@ -56,6 +56,9 @@ pub fn count_iterate_over_facet_distribution<'t, CB>(
 where
     CB: FnMut(&'t [u8], u64, DocumentId) -> Result<ControlFlow<()>>,
 {
+    /// # Important
+    /// The order of the fields determines the order in which the facet values will be returned.
+    /// This struct is inserted in a BinaryHeap and popped later on.
     #[derive(Debug, PartialOrd, Ord, PartialEq, Eq)]
     struct LevelEntry<'t> {
         /// The number of candidates in this entry.