Index: gc_lang/fr/modules-js/conj.js
==================================================================
--- gc_lang/fr/modules-js/conj.js
+++ gc_lang/fr/modules-js/conj.js
@@ -86,47 +86,49 @@
     getSimil: function (sWord, sMorph, bSubst=false) {
         if (!sMorph.includes(":V")) {
             return new Set();
         }
         let sInfi = sMorph.slice(1, sMorph.indexOf(" "));
-        let tTags = this._getTags(sInfi);
         let aSugg = new Set();
-        if (!bSubst) {
-            // we suggest conjugated forms
-            if (sMorph.includes(":V1")) {
-                aSugg.add(sInfi);
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":2p"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":1s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":3s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":3p"));
-            } else if (sMorph.includes(":V2")) {
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":1s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
-            } else if (sMorph.includes(":V3")) {
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":1s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Is", ":1s"));
-                aSugg.add(this._getConjWithTags(sInfi, tTags, ":Is", ":3s"));
-            } else if (sMorph.includes(":V0a")) {
-                aSugg.add("eus");
-                aSugg.add("eut");
-            } else {
-                aSugg.add("étais");
-                aSugg.add("était");
-            }
-            aSugg.delete("");
-        } else {
-            // we suggest past participles
-            aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q1"));
-            aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q2"));
-            aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q3"));
-            aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q4"));
-            aSugg.delete("");
-            // if there is only one past participle (epi inv), unreliable.
-            if (aSugg.size === 1) {
-                aSugg.clear();
+        let tTags = this._getTags(sInfi);
+        if (tTags) {
+            if (!bSubst) {
+                // we suggest conjugated forms
+                if (sMorph.includes(":V1")) {
+                    aSugg.add(sInfi);
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":2p"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":1s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":3s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Iq", ":3p"));
+                } else if (sMorph.includes(":V2")) {
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":1s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
+                } else if (sMorph.includes(":V3")) {
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":1s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Ip", ":3s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Is", ":1s"));
+                    aSugg.add(this._getConjWithTags(sInfi, tTags, ":Is", ":3s"));
+                } else if (sMorph.includes(":V0a")) {
+                    aSugg.add("eus");
+                    aSugg.add("eut");
+                } else {
+                    aSugg.add("étais");
+                    aSugg.add("était");
+                }
+                aSugg.delete("");
+            } else {
+                // we suggest past participles
+                aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q1"));
+                aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q2"));
+                aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q3"));
+                aSugg.add(this._getConjWithTags(sInfi, tTags, ":PQ", ":Q4"));
+                aSugg.delete("");
+                // if there is only one past participle (epi inv), unreliable.
+                if (aSugg.size === 1) {
+                    aSugg.clear();
+                }
             }
         }
         return aSugg;
     },
 
@@ -181,20 +183,23 @@
 class Verb {
 
     constructor (sVerb, sVerbPattern="") {
         // conjugate a unknown verb with rules from sVerbPattern
         if (typeof sVerb !== "string" || sVerb === "") {
-            throw new TypeError ("The value should be a non-empty string");
+            throw new TypeError ("The value should be a non-empty string.");
         }
         if (sVerbPattern.length == 0) {
             sVerbPattern = sVerb;
         }
         this.sVerb = sVerb;
         this.sVerbAux = "";
         this._sRawInfo = conj.getVtyp(sVerbPattern);
         this.sInfo = this._readableInfo(this._sRawInfo);
         this._tTags = conj._getTags(sVerbPattern);
+        if (!this._tTags) {
+            throw new RangeError ("Unknown verb.");
+        }
         this._tTagsAux = conj._getTags(this.sVerbAux);
         this.bProWithEn = (this._sRawInfo[5] === "e");
         this.cGroup = this._sRawInfo[0];
         this.dConj = new Map ([
             [":Y", new Map ([

Index: gc_lang/fr/modules/conj.py
==================================================================
--- gc_lang/fr/modules/conj.py
+++ gc_lang/fr/modules/conj.py
@@ -57,62 +57,63 @@
 
 def getSimil (sWord, sMorph, bSubst=False):
     if ":V" not in sMorph:
         return set()
     sInfi = sMorph[1:sMorph.find(" ")]
-    tTags = _getTags(sInfi)
-    aSugg = set()
-    #if ":Q" in sMorph or ":Y" in sMorph:
-    if not bSubst:
-        # we suggest conjugated forms
-        if ":V1" in sMorph:
-            aSugg.add(sInfi)
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":2p"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":1s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3p"))
-        elif ":V2" in sMorph:
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":1s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
-        elif ":V3" in sMorph:
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":1s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":1s"))
-            aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":3s"))
-        elif ":V0a" in sMorph:
-            aSugg.add("eus")
-            aSugg.add("eut")
-        else:
-            aSugg.add("étais")
-            aSugg.add("était")
-        aSugg.discard("")
-    else:
-        # we suggest past participles
-        aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q1"))
-        aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q2"))
-        aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q3"))
-        aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q4"))
-        aSugg.discard("")
-        # if there is only one past participle (epi inv), unreliable.
-        if len(aSugg) == 1:
-            aSugg.clear()
+    aSugg = set()
+    tTags = _getTags(sInfi)
+    if tTags:
+        if not bSubst:
+            # we suggest conjugated forms
+            if ":V1" in sMorph:
+                aSugg.add(sInfi)
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":2p"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":1s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3p"))
+            elif ":V2" in sMorph:
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":1s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
+            elif ":V3" in sMorph:
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":1s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":3s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":1s"))
+                aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":3s"))
+            elif ":V0a" in sMorph:
+                aSugg.add("eus")
+                aSugg.add("eut")
+            else:
+                aSugg.add("étais")
+                aSugg.add("était")
+            aSugg.discard("")
+        else:
+            # we suggest past participles
+            aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q1"))
+            aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q2"))
+            aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q3"))
+            aSugg.add(_getConjWithTags(sInfi, tTags, ":PQ", ":Q4"))
+            aSugg.discard("")
+            # if there is only one past participle (epi inv), unreliable.
+            if len(aSugg) == 1:
+                aSugg.clear()
     return aSugg
 
 
 def getConjSimilInfiV1 (sInfi):
     if sInfi not in _dVerb:
         return set()
-    tTags = _getTags(sInfi)
     aSugg = set()
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":2s"))
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3s"))
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3p"))
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":1s"))
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":2p"))
-    aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":2p"))
-    aSugg.discard("")
+    tTags = _getTags(sInfi)
+    if tTags:
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":2s"))
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3s"))
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":3p"))
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Is", ":1s"))
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Ip", ":2p"))
+        aSugg.add(_getConjWithTags(sInfi, tTags, ":Iq", ":2p"))
+        aSugg.discard("")
     return aSugg
 
 
 def _getTags (sVerb):
     "returns tuple of tags (usable with functions _getConjWithTags and _hasConjWithTags)"
@@ -148,13 +149,13 @@
 
 class Verb ():
     def __init__ (self, sVerb, sVerbPattern=""):
         # conjugate a unknown verb with rules from sVerbPattern
         if not isinstance(sVerb, str):
-            raise TypeError
+            raise TypeError("sVerb should be a string")
         if not sVerb:
-            raise ValueError
+            raise ValueError("Empty string.")
 
         if sVerbPattern == "":
             sVerbPattern = sVerb
 
         self.sVerb = sVerb
@@ -161,10 +162,12 @@
         self.sVerbAux = ""
         self._sRawInfo = getVtyp(sVerbPattern)
         self.sInfo = self._readableInfo()
         self.bProWithEn = (self._sRawInfo[5] == "e")
         self._tTags = _getTags(sVerbPattern)
+        if not self._tTags:
+            raise ValueError("Unknown verb.")
         self._tTagsAux = _getTags(self.sVerbAux)
         self.cGroup = self._sRawInfo[0];
         self.dConj = {
             ":Y": {
                 "label": "Infinitif",