Page 59 of Learner English: A Teacher's Guide to Interference reads:
There is a tense in French which is formed like the English past perfect, and its usage corresponds generally to the English tense. But it can also be used when the action spoken about is separated from the present by facts that are common knowledge to the speakers - even though they may not be mentioned:
‘Yes, I am in Room 232.’ *‘But I had asked for a double room!’
Is the sentence really ungrammatical though?