diff --git a/src/common.js b/src/common.js
index 35a37f194b..bb3eaf986c 100644
--- a/src/common.js
+++ b/src/common.js
@@ -1386,7 +1386,13 @@
         },
         complete_value: function(field, value) {
             var complete_boolean = function() {
-                return value ? [true] : [false];
+                if ((value === null) || (value === undefined)) {
+                    return [true, false];
+                } else if (value) {
+                    return [false];
+                } else {
+                    return [true];
+                }
             };
 
             var complete_selection = function() {
@@ -1848,9 +1854,8 @@
                                     return test.toLowerCase().startsWith(
                                         value.toLowerCase());
                                 });
-                    } else {
-                        return Boolean(value);
                     }
+                    return null;
                 },
                 'float': function() {
                     var factor = Number(field.factor || 1);
@@ -1966,10 +1971,12 @@
 
             var converts = {
                 'boolean': function() {
-                    if (value) {
+                    if (value === false) {
+                        return Sao.i18n.gettext('False');
+                    } else if (value) {
                         return Sao.i18n.gettext('True');
                     } else {
-                        return Sao.i18n.gettext('False');
+                        return '';
                     }
                 },
                 'integer': function() {
diff --git a/tests/sao.js b/tests/sao.js
index 314dcba88f..5d0e44f287 100644
--- a/tests/sao.js
+++ b/tests/sao.js
@@ -1308,7 +1308,7 @@
         ['False', false],
         ['no', false],
         ['0', false],
-        [null, false]
+        [null, null],
         ].forEach(test_func, field);
 
         field = {
@@ -1553,7 +1553,7 @@
         [
         [true, 'True'],
         [false, 'False'],
-        [null, 'False']
+        [null, '']
         ].forEach(test_func, field);
 
         field = {
@@ -1812,6 +1812,15 @@
                         ', ' + JSON.stringify(value) + ')');
         };
 
+        field = {
+            'type': 'boolean',
+        };
+        [
+            [null, [true, false]],
+            [true, [false]],
+            [false, [true]],
+        ].forEach(test_func, field);
+
         field = {
             'type': 'selection',
             'selection': [
@@ -2536,6 +2545,21 @@
         });
         QUnit.ok(compare(parser.completion('Relatio'),
             ["Relation: ", "Relation.Name: "]));
+
+        parser = new Sao.common.DomainParser({
+            'name': {
+                'string': "Active",
+                'name': 'active',
+                'type': 'boolean',
+            },
+        });
+        QUnit.ok(compare(parser.completion("Act"), ["Active: "]));
+        QUnit.ok(compare(parser.completion("Active:"),
+            ["Active: ", "Active: True", "Active: False"]));
+        QUnit.ok(compare(parser.completion("Active: t"),
+            ["Active: True", "Active: False"]));
+        QUnit.ok(compare(parser.completion("Active: f"),
+            ["Active: False", "Active: True"]));
     });
 
         /*