diff --git a/src/Configuration.java b/src/Configuration.java
index 26224c3..3f804cf 100644
--- a/src/Configuration.java
+++ b/src/Configuration.java
@@ -9,16 +9,24 @@ import java.util.Set;
 public class Configuration implements fr.istic.nplouzeau.cartaylor.api.Configuration {
     private Set<PartType> selectedParts;
     private CompatibilityManager compatibilityManager;
+    private static int NB_CATEGORY = 4;
          
 
     @Override
     public boolean isValid() {
-        if ( this.isComplete()){
-            
-            return true;
-                
+        if (this.isComplete()){
+            for(PartType pt: selectedParts){
+                //Verifier Requirements
+                for(PartType require : compatibilityManager.getRequirements(pt)){
+                    if(!selectedParts.contains(pt)) return false;
+                }
+                //Verifier Incompabilities
+                for(PartType incompa : compatibilityManager.getIncompatibilities(pt)){
+                    if(selectedParts.contains(pt)) return false;
+                }                
             }
-        else{
+            return true;
+        }else{
             return false;
         }
     }
@@ -26,7 +34,7 @@ public class Configuration implements fr.istic.nplouzeau.cartaylor.api.Configura
 
     @Override
     public boolean isComplete() {
-        if(selectedParts.size()==4){
+        if(selectedParts.size()==NB_CATEGORY){
             return true;
         }
         return false;