diff --git a/source/components/conversation/FormDecorator.js b/source/components/conversation/FormDecorator.js
index 5c8ff0ad0..53b166757 100644
--- a/source/components/conversation/FormDecorator.js
+++ b/source/components/conversation/FormDecorator.js
@@ -5,6 +5,7 @@ import { getFormatersFromUnit } from 'Engine/format'
 import React from 'react'
 import { useDispatch, useSelector } from 'react-redux'
 import { situationSelector } from 'Selectors/analyseSelectors'
+import { useTranslation } from 'react-i18next'
 
 /*
 This higher order component wraps "Form" components (e.g. Question.js), that represent user inputs,
@@ -15,9 +16,10 @@ to understand those precious higher order components.
 */
 
 export const FormDecorator = formType => RenderField =>
-	function({ fieldName, question, inversion, unit, ...otherProps }) {
+	function FormStep({ fieldName, question, inversion, unit, ...otherProps }) {
 		const dispatch = useDispatch()
 		const situation = useSelector(situationSelector)
+		const { language } = useTranslation().i18n
 
 		const submit = source =>
 			dispatch({
@@ -30,7 +32,7 @@ export const FormDecorator = formType => RenderField =>
 			dispatch(updateSituation(fieldName, normalize(value)))
 		}
 
-		const { format, normalize } = getFormatersFromUnit(unit)
+		const { format, normalize } = getFormatersFromUnit(unit, language)
 		const value = format(situation[fieldName])
 
 		return (
@@ -48,6 +50,7 @@ export const FormDecorator = formType => RenderField =>
 						setFormValue={setFormValue}
 						submit={submit}
 						format={format}
+						normalize={normalize}
 						unit={unit}
 						{...otherProps}
 					/>
diff --git a/source/components/conversation/Input.js b/source/components/conversation/Input.js
index 8e32f1cd8..9f62406fc 100644
--- a/source/components/conversation/Input.js
+++ b/source/components/conversation/Input.js
@@ -2,7 +2,7 @@ import classnames from 'classnames'
 import { T } from 'Components'
 import withColours from 'Components/utils/withColours'
 import { compose } from 'ramda'
-import React, { useCallback, useState } from 'react'
+import React, { useCallback } from 'react'
 import { usePeriod } from 'Selectors/analyseSelectors'
 import { debounce } from '../../utils'
 import { FormDecorator } from './FormDecorator'
@@ -33,7 +33,7 @@ export default compose(
 				<InputSuggestions
 					suggestions={suggestions}
 					onFirstClick={value => {
-						setFormValue(format(value))
+						setFormValue(value)
 					}}
 					onSecondClick={() => submit('suggestion')}
 					rulePeriod={rulePeriod}
@@ -45,7 +45,7 @@ export default compose(
 					type="text"
 					key={value}
 					autoFocus
-					defaultValue={value}
+					value={format(value)}
 					onChange={evt => {
 						debouncedSetFormValue(evt.target.value)
 					}}
diff --git a/source/engine/format.js b/source/engine/format.js
new file mode 100644
index 000000000..87216f700
--- /dev/null
+++ b/source/engine/format.js
@@ -0,0 +1,96 @@
+import { serialiseUnit } from 'Engine/units'
+import { memoizeWith } from 'ramda'
+
+export const formatCurrency = (value, language) => {
+	return value == null
+		? ''
+		: Intl.NumberFormat(language, {
+				style: 'currency',
+				currency: 'EUR',
+				maximumFractionDigits: 0,
+				minimumFractionDigits: 0
+		  })
+				.format(value)
+				.replace(/^(-)?€/, '$1€\u00A0')
+}
+
+const sanitizeValue = language => value =>
+	language === 'fr' ? String(value).replace(',', '.') : value
+
+export const formatPercentage = value => +(value * 100).toFixed(2)
+export const normalizePercentage = value => value / 100
+
+export const getFormatersFromUnit = (unit, language = 'en') => {
+	const serializedUnit = typeof unit == 'object' ? serialiseUnit(unit) : unit
+	const sanitize = sanitizeValue(language)
+	switch (serializedUnit) {
+		case '%':
+			return {
+				format: numberFormatter({ style: 'percent', language }).replace(
+					' %',
+					''
+				),
+				normalize: v => normalizePercentage(language)(sanitize(v))
+			}
+		default:
+			return {
+				format: x =>
+					Number(x)
+						? numberFormatter({ style: 'decimal', language })(Number(x))
+						: x,
+				normalize: x => sanitize(x)
+			}
+	}
+}
+
+const NumberFormat = memoizeWith(
+	(...args) => JSON.stringify(args),
+	Intl.NumberFormat
+)
+
+export let numberFormatter = ({
+	style,
+	maximumFractionDigits = 2,
+	minimumFractionDigits = 0,
+	language
+}) => value =>
+	NumberFormat(language, {
+		style,
+		currency: 'EUR',
+		maximumFractionDigits,
+		minimumFractionDigits
+	}).format(value)
+
+export function formatValue({
+	maximumFractionDigits,
+	minimumFractionDigits,
+	language,
+	unit,
+	value
+}) {
+	const serializedUnit = typeof unit == 'object' ? serialiseUnit(unit) : unit
+
+	switch (serializedUnit) {
+		case '€':
+			return numberFormatter({
+				style: 'currency',
+				maximumFractionDigits,
+				minimumFractionDigits,
+				language
+			})(value)
+		case '%':
+			return numberFormatter({ style: 'percent', maximumFractionDigits })(value)
+		default:
+			if (typeof value !== 'number') {
+				return value
+			}
+			return (
+				numberFormatter({
+					style: 'decimal',
+					minimumFractionDigits,
+					maximumFractionDigits
+				})(value) +
+				(typeof serializedUnit === 'string' ? `\u00A0${serializedUnit}` : '')
+			)
+	}
+}