Fix issue with flatpage base url

playground/templates/playground/underscore/about.mtpl

 {% load flatpages %}
 
-{% get_flatpages '/la-notation-w/' as about_pages_fr %}
-{% get_flatpages '/la-notation-w/en/' as about_pages_en %}
+{% get_flatpages '/fr/la-notation-w/' as about_pages_fr %}
+{% get_flatpages '/en/la-notation-w/' as about_pages_en %}
 
 <div class="is-en">
     {% for page in about_pages %}

playground/templates/playground/underscore/credits.mtpl

 {% load flatpages %}
-{% get_flatpages '/credits/' as credits_pages_fr %}
-{% get_flatpages '/credits/en/' as credits_pages_en %}
+{% get_flatpages '/fr/credits/' as credits_pages_fr %}
+{% get_flatpages '/en/credits/' as credits_pages_en %}
 
 <div class="is-fr">
     {% for page in credits_pages_fr %}

playground/templates/playground/underscore/home.mtpl

 {% load flatpages %}
 
-{% get_flatpages '/introduction/' as intro_pages_fr %}
-{% get_flatpages '/introduction/en/' as intro_pages_en %}
+{% get_flatpages '/fr/introduction/' as intro_pages_fr %}
+{% get_flatpages '/en/introduction/' as intro_pages_en %}
 
 <div class="intro body-text body-text--about">
     {# Poor man translation: only show selected language using CSS #}