FLT CREW IS CHALLENGED BY LFFF ARTCC RADAR CTLR WHEN OBSERVING CONTINUED DESCENT WHEN LEVEL OFF WAS EXPECTED. CTLRS FRENCH/ENGLISH PHRASEOLOGY MIX IS CAUSE OF ALT OVERSHOOT AS FLT CREW CLARIFY ALT ASSIGNMENT.

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WHILE FLYING TO PARIS; FRANCE (LFPG) WE ENTERED FRENCH AIRSPACE FROM THE E AT FL340 ON A DIRECT TO FIX CLRNC. AFTER APPROX 10 MINS OF FRENCH CTL; WE WERE GIVEN DESCENT INSTRUCTIONS. I WAS ACTING AS PLT NOT FLYING AND THE FO WAS ACTING AT PLT FLYING. AS UNDERSTOOD BY US; THE FOLLOWING INSTRUCTIONS WERE GIVEN BY ATC: 'ACR X; DESCEND TO FL230.' 'ACR X IS LEAVING FL340 FOR FL230.' (FL230 IS ENTERED IN FCP AND CONFIRMED BY PNF.) A SHORT PAUSE. 'ACR X; DESCEND TO FL230.' WE ACKNOWLEDGED; 'ROGER; ACR X IS DESCENDING TO FL230.' WHEN PASSING FL330; ATC ASKED; 'ACR X; MAINTAIN FL230.' WE RESPONDED AGAIN; 'ACR X UNDERSTANDS; DESCEND TO FL230.' ATC RESPONDED; 'NEGATIVE; MAINTAIN FL230.' THIS IS WHEN WE HAD A COCKPIT DISCUSSION. WE RESPONDED; 'CTL; IS THE NEW; FL330?' AND ATC RESPONDED WITH; 'AFFIRMATIVE.' CLIMB WAS INITIATED BY PF FROM FL32.8 BACK TO FL330. NO FURTHER COMMENTS FROM FRENCH ATC. IN RETROSPECT; I BELIEVE THE CTLR WAS MIXING FRENCH AND ENGLISH. I BELIEVE HE WAS RAPIDLY SAYING; 'DESCEND TO FL DEUX (2) THREE ZERO; MEANING TWO THREES AND A ZERO.' AT NO TIME DID MYSELF OR THE PF(BOTH VERY EXPERIENCED INTERNATIONAL PLTS) THINK THAT THE CTLR WAS SAYING ANYTHING OTHER THAN FL230. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: AFTER THE CTLR QUESTIONED THE FLT CREW A SECOND TIME; THE RPTR SAID THE CREW BEGAN TO QUESTION THE APPARENT WORD 'TWO'; REALIZING THE CTLR WAS PROBABLY MIXING FRENCH WITH ENGLISH BY USING THE FRENCH WORD 'DEUX.' THE RPTR STATED THE CREW WAS A WELL SEASONED INTERNATIONAL FLT CREW. THE RPTR STATED THAT FRENCH CTLRS OFTEN MIX CTL INSTRUCTIONS BETWEEN FRENCH AND ENGLISH IN THE SAME CLRNC AS IT HAPPENED IN THIS INCIDENT.