diff --git a/source/actions/actions.js b/source/actions/actions.js
index 6f330e623..1fe6bf54a 100644
--- a/source/actions/actions.js
+++ b/source/actions/actions.js
@@ -67,6 +67,11 @@ export const updateSituation = (fieldName, value) => ({
 	value
 })
 
+export const updatePeriod = toPeriod => ({
+	type: 'UPDATE_PERIOD',
+	toPeriod
+})
+
 // $FlowFixMe
 export function setExample(name, situation, dottedName) {
 	return { type: 'SET_EXAMPLE', name, situation, dottedName }
diff --git a/source/components/PeriodSwitch.js b/source/components/PeriodSwitch.js
index e0225cc41..34bba977d 100644
--- a/source/components/PeriodSwitch.js
+++ b/source/components/PeriodSwitch.js
@@ -1,3 +1,4 @@
+import { updatePeriod } from 'Actions/actions'
 import React from 'react'
 import { Trans } from 'react-i18next'
 import { useDispatch, useSelector } from 'react-redux'
@@ -12,10 +13,9 @@ export default function PeriodSwitch() {
 	)
 	const currentPeriod = situation.période
 	let periods = ['année', 'mois']
-	const updatePeriod = toPeriod => dispatch({ type: 'UPDATE_PERIOD', toPeriod })
 
 	if (!currentPeriod) {
-		updatePeriod(defaultPeriod)
+		dispatch(updatePeriod(defaultPeriod))
 	}
 
 	return (
@@ -27,7 +27,7 @@ export default function PeriodSwitch() {
 							name="période"
 							type="radio"
 							value={period}
-							onChange={() => updatePeriod(period)}
+							onChange={() => dispatch(updatePeriod(period))}
 							checked={currentPeriod === period}
 						/>
 						<span>
diff --git a/source/reducers/rootReducer.js b/source/reducers/rootReducer.js
index a5cc2cd37..de2612ee3 100644
--- a/source/reducers/rootReducer.js
+++ b/source/reducers/rootReducer.js
@@ -135,7 +135,7 @@ function updatePeriod(situation, { toPeriod, rules }) {
 	}
 }
 
-function simulation(state = null, action) {
+function simulation(state = null, action, rules) {
 	if (action.type === 'SET_SIMULATION') {
 		const { config, url } = action
 		return { config, url, hiddenControls: [], situation: {} }
@@ -162,7 +162,7 @@ function simulation(state = null, action) {
 				...state,
 				situation: updatePeriod(state.situation, {
 					toPeriod: action.toPeriod,
-					rules: action.rules
+					rules: rules
 				})
 			}
 	}
@@ -201,26 +201,23 @@ const existingCompanyReducer = (state, action) => {
 	}
 	return newState
 }
-export default (state, action) => {
-	// Enrich the action
-	if (action.type === 'UPDATE_PERIOD') {
-		action.rules = state.rules
-	}
-	return reduceReducers(
-		existingCompanyReducer,
-		storageReducer,
+
+export default reduceReducers(
+	existingCompanyReducer,
+	storageReducer,
+	(state, action) =>
 		combineReducers({
 			sessionId: defaultTo(Math.floor(Math.random() * 1000000000000) + ''),
 			conversationSteps,
 			lang,
 			rules: defaultTo(null),
-			simulation,
 			explainedVariable,
+			// We need to access the `rules` in the simulation reducer
+			simulation: (a, b) => simulation(a, b, state.rules),
 			previousSimulation: defaultTo(null),
 			currentExample,
 			situationBranch,
 			activeTargetInput,
 			inFranceApp: inFranceAppReducer
-		})
-	)(state, action)
-}
+		})(state, action)
+)