Conflict using french babel resulting in bibliography refs appearing in smallcaps

Question

I wanted to re-run my thesis and while I changed nothing (nor the file format, the bib file or anything), all my references in the text now appear in smallcaps. I suspect there is a conflict with the french babel package because when I remove

\usepackage[english,french]{babel} 

my biblio references appear in normal caps. But then all my chapter and section names are not in french anymore (abstract, listofigures, etc.). Any idea on how to solve this conflict?

here's the mwe

\pdfobjcompresslevel 0
\documentclass[12pt]{ociamthesis}  % default square logo 

\usepackage[english,french]{babel}% pour avoir les titres en français (table des matières, etc.)
 %%% UTILS %%%
\RequirePackage[utf8]{inputenc}
\RequirePackage[T1]{fontenc}
\RequirePackage{lmodern}
\usepackage[backend=bibtex,natbib=true,firstinits=true,style=authoryear,useprefix=true,url=false,doi=false,maxcitenames=2,maxbibnames=99,sorting=nyt]{biblatex}
\DefineBibliographyExtras{french}{\renewcommand*\mkbibnamelast[1]{#1}}
\setlength\bibitemsep{1.5\itemsep}% quelques options + compatibilité    natbib 
\usepackage{slbiblatex} % personalized package for biblio but does not have babel options
\addbibresource{BiblioThese.bib} % fichier bib

% Remove brackets from numbering in List of References
\makeatletter
\renewcommand{\@biblabel}[1]{\quad#1.}
\makeatother
\clearpage
\graphicspath{{figures/}}
%%%%%  latex en-tête %%%%%%%
\usepackage{fancyhdr}
\pagestyle{fancy}
\usepackage{afterpage}
\newcommand\blankpage{%
\null
\thispagestyle{empty}%
\addtocounter{page}{-1}%
\newpage}


 %%%% nom des figures
 \AtBeginDocument{%
 \renewcommand{\figurename}{Figure} % change figure appearance
  \renewcommand{\tablename}{Table} % change figure appearance
  }

  %load any additional packages
  \usepackage{amssymb}
  \usepackage{pdfpages}

   \usepackage{enumitem}% package pour enumérer en roman

   \newcommand{\aref}[1]{Appendix~\ref{#1}}
   \begin{document}
   \renewcommand{\bibname}{R\'ef\'erences bibliographiques}
  \baselineskip=24pt plus1pt

  %set the number of sectioning levels that get number and appear in the contents
 \setcounter{secnumdepth}{3}
 \setcounter{tocdepth}{2}

 \include{dedication}       
 \include{acknowlegements}   
 \include{abstract}          
 \renewcommand{\abstractname}{Abstract}
 \include{abstract-eng}          % include the abstract
 \begin{romanpages}          % start roman page numbering
 \tableofcontents       
 \listoffigures         
 \listoftables          
 \include{Listofpapers}
 \end{romanpages}            % end roman page numbering

 \include{introduction}
 \include{chapter2}
 \include{chapter3}
 \include{chapter4}
 \include{conclusions}
 \addcontentsline{toc}{chapter}{Conclusions et perspectives}

 \addcontentsline{toc}{chapter}{R\'ef\'erences bibliographiques}

 \printbibliography

 %now enable appendix numbering format and include any appendices
 \renewcommand\appendixname{Annexe}
 \appendix
 \include{appendix1}
 \include{appendix2}
 \include{appendix3}
 \include{appendix4}

\include{abstract-eng}      
\include{abstract}          
\end{document}