diff --git a/Configuration-file.md b/Configuration-file.md
new file mode 100644
index 0000000..b823dbf
--- /dev/null
+++ b/Configuration-file.md
@@ -0,0 +1,45 @@
+The configuration file is in JSON format. 
+
+default_config.json : 
+
+```
+{
+        "_SUMOCMD": "sumo",
+	"_SUMOCFG": "simulations/mulhouse_simulation/osm.sumocfg",
+	
+	"areas_number": 10,
+	"emissions_threshold": 500000, 
+	"n_steps": 200,
+	"window_size":100,
+	
+	"without_actions_mode": true,
+	
+	"limit_speed_mode": false,
+	"speed_rf": 0.1,
+	
+	"adjust_traffic_light_mode": false,
+	"trafficLights_duration_rf": 0.2,
+	
+	"weight_routing_mode": false,
+	
+	"lock_area_mode": false
+    
+}
+```
+You can change many settings through this file:
+
+* _SUMOCMD : Use 'sumo-gui' to launch the application with the GUI, 'sumo' without.
+* _SUMOCFG : Path to the scenario file *.sumocfg.
+
+* areas_number : choice of the map grid , this will create areas_number x areas_number areas.
+* emissions_threshold : threshold of pollutants emissions (in mg) beyond which the program acts on the areas. 
+* n_steps : Define the duration of the simulated time, one step corresponding to one simulated second.
+* window_size : size of acquisition window of pollutant emissions in areas. Each 'window_size' steps areas will return to normal if the emissions are below 'emissions_threshold'.
+
+* without_actions_mode : Set this mode to True if you want running a reference simulation without acting on areas. 
+You can also use -ref option in shell command. 
+* limit_speed_mode / speed_rf : The maximum speed in a too polluted area will be multiplied by a factor defined by 'speed_rf'. 
+* adjust_traffic_light_mode / trafficLights_duration_rf : The duration of the traffic lights will be multiplied by a factor defined by 'trafficLights_duration_rf'.
+
+* weight_routing_mode (HEAVY) : All vehicles calculate at each simulation step the least polluted route. This mode affects all traffic lanes by assigning them a "weight" corresponding to pollutant emissions on that lane. This mode is not recommended because it requires too much computing time. 
+* lock_area_mode (NOT FIXED) : Blocks an area that is too polluted to vehicles. This mode is not recommended because it is not fixed.