diff --git a/python/core/qgsauxiliarystorage.sip b/python/core/qgsauxiliarystorage.sip
index c0ade300cdd..aab4d251fd7 100644
--- a/python/core/qgsauxiliarystorage.sip
+++ b/python/core/qgsauxiliarystorage.sip
@@ -184,6 +184,11 @@ class QgsAuxiliaryStorage
 %Docstring
  Constructor.
 
+ The project filename is used to build a database path at the same
+ location, but with a different extension. Then, it's the same logic as
+.. seealso:: QgsAuxiliaryStorage(const QString &, bool copy).
+
+
  \param project The project for which the auxiliary storage has to be used
  \param copy Parameter indicating if a copy of the database has to be used
 %End
@@ -192,6 +197,21 @@ class QgsAuxiliaryStorage
 %Docstring
  Constructor.
 
+ If a valid database path is given in parameter and copy mode is
+ deactivated, then every changes is directly committed on the original
+ database. But if the copy mode is activated, then changes are committed
+ on a copy of the database (a temporary file) and a save action is
+ therefore necessary to keep modifications in the original file.
+
+ If an empty string for the database path is given in parameter, then
+ a database is created in a temporary file whatever the copy mode.
+
+ If the database path given in parameter is not empty but does not exist,
+ then a database is created at this location when copy mode is
+ deactivated. When copy mode is activated, a temporary database is used
+ instead and a save action will be necessary to create the database at
+ the original location given in parameter.
+
  \param filename The path of the database
  \param copy Parameter indicating if a copy of the database has to be used
 %End
diff --git a/src/core/qgsauxiliarystorage.h b/src/core/qgsauxiliarystorage.h
index 7aa0a9cdb76..e24e9a2a392 100644
--- a/src/core/qgsauxiliarystorage.h
+++ b/src/core/qgsauxiliarystorage.h
@@ -206,6 +206,11 @@ class CORE_EXPORT QgsAuxiliaryStorage
     /**
      * Constructor.
      *
+     * The project filename is used to build a database path at the same
+     * location, but with a different extension. Then, it's the same logic as
+     * described for \see QgsAuxiliaryStorage(const QString &, bool copy).
+     *
+     *
      * \param project The project for which the auxiliary storage has to be used
      * \param copy Parameter indicating if a copy of the database has to be used
      */
@@ -214,6 +219,21 @@ class CORE_EXPORT QgsAuxiliaryStorage
     /**
      * Constructor.
      *
+     * If a valid database path is given in parameter and copy mode is
+     * deactivated, then every changes is directly committed on the original
+     * database. But if the copy mode is activated, then changes are committed
+     * on a copy of the database (a temporary file) and a save action is
+     * therefore necessary to keep modifications in the original file.
+     *
+     * If an empty string for the database path is given in parameter, then
+     * a database is created in a temporary file whatever the copy mode.
+     *
+     * If the database path given in parameter is not empty but does not exist,
+     * then a database is created at this location when copy mode is
+     * deactivated. When copy mode is activated, a temporary database is used
+     * instead and a save action will be necessary to create the database at
+     * the original location given in parameter.
+     *
      * \param filename The path of the database
      * \param copy Parameter indicating if a copy of the database has to be used
      */