Free dictionary online: translation in English, Spanish, French, Italian, Chinese, Russian, definitions, synonyms...
Results found in several dictionaries: Collins, Collaborative Dictionary
box room 
  n 
  (=storeroom) débarras  m 
  (=small room) petite chambre  f  
It's just a box room with a desk and chair   

Collaborative Dictionary     English-French
dialog box n. la boîte de dialogue Reverso General Dictionary 
! powder room(slang) n. toilet for ladies 
labour room n. la salle de travail Reverso General Dictionary 
safe-deposit box n. le coffre-fort Reverso General Dictionary 
computer room n. la salle d'informatique Reverso General Dictionary 
rest room n. 1) les toilettes, 2) la salle de repos Reverso General Dictionary 
***
'box room' also found in translations in French-English dictionary
boxer nnpl. 1) box (vt), 2) box (vi) Reverso General Dictionary 
Le boîtier d'unité centrale FRU est une nouvelle station de travail : n. The FRU CPU box is a new workstation: ~ 
caisse n. 1) box (f), 2) cash desk (f) Reverso General Dictionary 
boîte déroulante nm. drop-down box Reverso General Dictionary 
nuit d'hôtel nm. hotel room night Reverso General Dictionary 
salle d'informatique nm. computer room Reverso General Dictionary 
salle de danse nm. dancing room Reverso General Dictionary 
Le boîtier d'unité centrale FRU est une station de travail qui a déjà été réparée : n. The FRU CPU box is already a repaired workstation. ~ 
carton n. 1) cardboard (m), 2) box (m) Reverso General Dictionary 
déshabilloir pref. changing room Reverso General Dictionary 
jardinière n. 1) gardener (f), 2) window box (f) Reverso General Dictionary 
vestiaire n. 1) cloakroom (m), 2) changing room (m) Reverso General Dictionary 
boîte d'archives nm. file box Reverso General Dictionary 
boîte postale nm. post office box Reverso General Dictionary 
living room pref. living room Reverso General Dictionary 
shadow boxing pref. shadow boxing Reverso General Dictionary 
boîte à archives nm. file box Reverso General Dictionary 
boîte à bijoux nm. jewellery box Reverso General Dictionary 

"Collins English French Electronic Dictionary © HarperCollins Publishers 2005"