Oui, English to French !!

when i was working in Louvre Museum, everyday i left behind me thousands of visitors...
Hearing how well fluent i was in english, a french speaking man, asked me 'vous parlez francais ?' : do u speak french ? In his own country,in the reputed rich french museum the poor guy had to ask that to a employee...to seek help in buying his ticket. i was surprised, so i asked him " who ? me ? yes of course !!"
this is nothing. once i was helping a french guy out with his ticket thing (this time in french ofcourse), and someone called me from behind," excuse me.." actively i replied 'yes?' the same FAQss..!!
Having satisfied this visitor ,then when i came back to this french speaking guy in front of me, i continued with him in ..guess what? !! in english forgetting we were talking in french..
"ya, so Please insert 10, 20 or 5 euros..try these !". man said "yes, i am "..then with a pause of few minutes he asked me " mais pourquoi vous me parlez en anglais ?" ( but why the hell was I talking to him in english suddenly)
ohhh!! Not even aware this silly girl continues..."did i speak english with u ?" Man replied " Oui, vous avez dit ...please try these euros for..." !! Oh i apologized !!I was about to explose in a big laughter, but i controlled. I said "oh je suis désolée , mais ca arrive ". Working all the day with much more of my english brought me to this situation. Actually I was very happy ,after such a long time I was gettig to speak english freely and with Britishers, americans, australians and....Indians !