diff --git a/Plugin/src/SofaPython3/PythonFactory.cpp b/Plugin/src/SofaPython3/PythonFactory.cpp
index bb200c73..c20da562 100644
--- a/Plugin/src/SofaPython3/PythonFactory.cpp
+++ b/Plugin/src/SofaPython3/PythonFactory.cpp
@@ -291,16 +291,27 @@ void copyFromListOf<std::string>(BaseData& d, const AbstractTypeInfo& nfo, const
 
 void PythonFactory::fromPython(BaseData* d, const py::object& o)
 {
-
     const AbstractTypeInfo& nfo{ *(d->getValueTypeInfo()) };
 
+    // Is this data field a container ?
+    // If no we fill it with direct access.
     if(!nfo.Container())
     {
         scoped_writeonly_access guard(d);
         if(nfo.Integer()) {
             nfo.setIntegerValue(guard.ptr, 0, py::cast<int>(o));
         } else if(nfo.Text()) {
-            nfo.setTextValue(guard.ptr, 0, py::cast<py::str>(o));
+            if(py::isinstance<py::str>(o))
+            {
+                nfo.setTextValue(guard.ptr, 0, py::cast<py::str>(o));
+            }
+            else
+            {
+                std::stringstream s;
+                s<< "trying to set value for '"
+                 << d->getName() << "' from a python object of type " << py::cast<std::string>(py::str(o.get_type()))  ;
+                throw std::runtime_error(s.str());
+            }
         } else if(nfo.Scalar()) {
             nfo.setScalarValue(guard.ptr, 0, py::cast<double>(o));
         } else {
@@ -328,6 +339,18 @@ void PythonFactory::fromPython(BaseData* d, const py::object& o)
         return ;
     }
 
+    // The data field is a container, and we want to sets its value from a python string.
+    // This is the old sofa-behavior that we want to avoid.
+    // To smooth the deprecation process we are still allowing it ...but prints a warning.
+    if( !nfo.Text() && py::isinstance<py::str>(o) )
+    {
+        msg_deprecated(d->getOwner()) << "Data field '" << d->getName() << "' is initialized from a string."
+                                      << " This behavior was allowed with SofaPython2 but have very poor performance so it is now "
+                                      << "deprecated with SofaPython3. Please fix your scene (as this behavior will be removed).";
+        d->read( py::cast<std::string>(o) );
+        return;
+    }
+
     if(nfo.Integer())
         return copyFromListOf<int>(*d, nfo, o);
 
@@ -341,7 +364,7 @@ void PythonFactory::fromPython(BaseData* d, const py::object& o)
 
     std::stringstream s;
     s<< "binding problem, trying to set value for "
-     << d->getName() << ", " << py::cast<std::string>(py::str(o));
+     << d->getName() << ", from " << py::cast<std::string>(py::str(o.get_type()));
     throw std::runtime_error(s.str());
 }
 
diff --git a/bindings/Sofa/tests/Core/BaseData.py b/bindings/Sofa/tests/Core/BaseData.py
index b0cf3e47..34d99d9a 100644
--- a/bindings/Sofa/tests/Core/BaseData.py
+++ b/bindings/Sofa/tests/Core/BaseData.py
@@ -292,6 +292,13 @@ def t(c):
             self.assertEqual(wa[2, 2], 8.0)
             numpy.testing.assert_array_equal(wa, v*4.0)
 
+    def test_set_value_from_string(self):
+        n = create_scene("rootNode")
+        n.gravity.value = [1.0,2.0,3.0]
+        self.assertEqual(list(n.gravity.value), [1.0,2.0,3.0])
+        n.gravity.value = "4.0 5.0 6.0"
+        self.assertEqual(list(n.gravity.value), [4.0,5.0,6.0])
+
     def test_DataString(self):
         n = create_scene("rootNode")
         self.assertTrue(isinstance(n.name, Sofa.Core.DataString))