diff --git a/README.md b/README.md
index 2cb318c..73feeff 100644
--- a/README.md
+++ b/README.md
@@ -8,8 +8,10 @@ This app is made of two parts: a client webapp and a server part to store and
 serve the issues. This code is the code running behind https://cyclo.phyks.me/.
 
 As of current version, only the client side part (code running on your local
-device) handles your geolocation. **Your geolocation is never sent** to the
-server or any external resource.
+device) handles your geolocation. **Your precise geolocation is never sent**
+to the server or any external resource. However, the map background is
+downloaded on demand from [Thunderforest](http://thunderforest.com/) so they
+could know the location of the displayed map.
 
 ## OpenData
 
diff --git a/src/components/About.vue b/src/components/About.vue
index 8860681..8cc1649 100644
--- a/src/components/About.vue
+++ b/src/components/About.vue
@@ -2,7 +2,7 @@
     <v-container fluid>
         <v-layout row>
             <v-flex xs12 sm6 offset-sm3>
-                <p>{{ $t('about.summary') }} {{ $t('about.geolocationDescription') }}</p>
+                <p>{{ $t('about.summary') }} <span v-html="$t('about.geolocationDescription')"></span></p>
 
                 <h2 class="body-2">{{ $t('about.usage') }}</h2>
                 <p>{{ $t('about.usageDescription') }}</p>
diff --git a/src/i18n/en.js b/src/i18n/en.js
index 9435d26..20dcd5b 100644
--- a/src/i18n/en.js
+++ b/src/i18n/en.js
@@ -2,7 +2,7 @@
 export default {
     about: {
         availableReportsTitle: 'The available reports so far are:',
-        geolocationDescription: 'As of current version, your geolocation is handled within your device and never sent from it to any external service.',
+        geolocationDescription: 'As of current version, your precise geolocation is handled within your device and never sent from it to any external service. The map background is downloaded on demand from <a href="http://thunderforest.com/">Thunderforest</a> and they have then access to an estimate of the displayed position.',
         license: 'It is released under an <a href="https://opensource.org/licenses/MIT">MIT license</a> (<a href="https://framagit.org/phyks/cyclassist">source code</a>). Icons are based on creations from Wikimedia and Vecteezy. The map background is using tiles from <a href="https://www.opencyclemap.org/docs/">OpenCycleMap</a>, thanks to <a href="https://www.openstreetmap.org/copyright">OpenStreetMap contributors</a> and <a href="http://leafletjs.com/">Leaflet</a>. Collected reports are available under <a href="https://opendatacommons.org/licenses/odbl/">ODbL license</a>.',
         summary: 'This app lets you track and share issues with bike lanes.',
         usage: 'How to use',
diff --git a/src/i18n/fr.js b/src/i18n/fr.js
index fde18b1..4cd8d82 100644
--- a/src/i18n/fr.js
+++ b/src/i18n/fr.js
@@ -2,7 +2,7 @@
 export default {
     about: {
         availableReportsTitle: "Les signalements disponibles pour l'instant sont :",
-        geolocationDescription: "Dans la version actuelle, votre position est traitée directement par votre appareil et n'est jamais envoyée à un service externe.",
+        geolocationDescription: "Dans la version actuelle, votre position est traitée directement par votre appareil et n'est jamais envoyée à un service externe. Le fond de carte est téléchargé à la demande depuis <a href='http://thunderforest.com/'>Thunderforest</a> et ils ont donc accès à une estimation de la position affichée.",
         license: "Le code source est sous <a href='https://opensource.org/licenses/MIT'>licence MIT license</a> (<a href='https://framagit.org/phyks/cyclassist'>code source</a>). Les icones sont basées sur des travaux de Wikimedia et Vecteezy. Les tuiles de fond de carte proviennent de chez <a href='https://www.opencyclemap.org/docs/'>OpenCycleMap</a>, grace aux <a href='https://www.openstreetmap.org/copyright'>contributeurs OpenStreetMap</a> et à <a href='http://leafletjs.com/'>Leaflet</a>. Les signalements sont disponibles sous <a href='https://opendatacommons.org/licenses/odbl/'>licence ODbL</a>.",
         summary: 'Cette application vous permet de signaler et de partager des problèmes avec les itinéraires cyclables.',
         usage: 'Utilisation',