Usage of the Pluperfect Subjunctive 
The French pluperfect subjunctive is the least common literary tense - it's the literary equivalent of the past subjunctive.
Like all literary tenses, the pluperfect subjunctive is used only in literature, historical writings, and other very formal writing, so it is important to be able to recognize it but chances are that you will never in your life need to conjugate it.
Formation of the Pluperfect Subjunctive 
- The pluperfect subjunctive is a compound tense- it consists of two verbs, the auxiliary verb and the past participle of the verb one seeks to use in this tense.
- The auxiliary verb is conjugated as if it were being used in the imperfect subjunctive.
- The past participle is added immediately after the auxiliary verb.
- A negative structure such as ne ... pas is always placed around the auxiliary verb, immediately before the past participle.