Dear Fabienne,

I view <abstract> as a combination of both a general biographical/historical note and a scope/content note.
I use <abstract> only in the <archdesc> (collection-level) field because I'm assuming that in the future all of the <abstracts> of my finding aids can be extracted and used to give the researcher an overall view of the collections of my library.  I don't want to cloud that function by inserting <abstract> tags within the finding aid.

I have been using the <scopecontent> and <note> tags extensively in my component cataloging, not only to summarize a series' contents, but also to list specific items of interest or to supply additional information that might assist the researcher. In the examples you provide, I would use <scopecontent> in instances 1, 3 & 4.  You could also use if for instance 2 (Le manuscrit est incomplet de la fin...) but I would use <note> instead, since the information is about what is not there, rather than about what is there.  I also use the <note> field as a "see also" reference to another series with similar subject strengths.

I hope that this is helpful, sincerely,
Alison Hinderliter
The Newberry Library, Chicago US

> > Examples:
> > <c01><did><unitid>Ms. 5.</unitid><unittitle>"Tractatus de sacramento > matrimonii, par Monsieur Halé, docteur de Sorbonne"</unittitle>
> <unitdate>XVIIe siècle</unitdate><physdesc>Papier. 254 feuillets. 370 > sur 230 millim.</physdesc></did>
>  ?Fol. 1 v°. Note sur M. Halé et sur ses ouvrages.?</c01>

> > <c01><did><unitid>Ms. 1.</unitid><unittitle>S. Augustin, Cité de Dieu, > traduction de Raoul de Presles.</unittitle>
> <unitdate>XVe siècle</unitdate><physdesc>Papier. 376 feuillets. 380 > sur 280 millim.</physdesc></did>
> ?Le manuscrit est incomplet de la fin et le texte s'arrête au milieu > du livre IV. Miniature et encadrement sur vélin au fol. IIII.?</c01>

> > <c01><did><unitid>Ms. 12.</unitid><unittitle>"Le Miroir des curés, en > deux livres"</unittitle>
> <unitdate>XVe siècle</unitdate><physdesc>Papier. 280 et 248 feuillets. > 282 sur 210 millim.</physdesc></did>
> ?Sorte de manuel contenant des instructions morales, des sermons pour > les divers temps de l'année, des vies de saints, etc.?

> <c02><did><unittitle>Livre I</unittitle></c02>
> <c02><did><unittitle>Livre II</unittitle></c02>
> ?On lit sur le premier feuillet"Ce livre est à Mademoiselle...". > Initiales et titre en rouge.
> </c01>