% biblatex-dw:
% \usepackage[style=footnote-dw, xref=true, loccittracker, opcittracker,
% autopunct=false, ibidemfont=italic, idemfont=italic,
% citeauthorname=firstfull, idembibformat=dash, nopublisher=false,
% annotation=true, pageref=true, journalnumber=date,
% acronyms=true]{biblatex}

% \renewcommand{\mkbibacro}[1]{%
%   \textls[55]{\scalefont{0.95}#1}\isdot}
% \renewcommand{\labelnamepunct}{\addperiod\space}
% \DeclareLanguageMapping{french}{french-dw}
% \DeclareFieldFormat[book]{title}{\mkbibemph{#1}}
% \DeclareFieldFormat[book]{citetitle}{\mkbibemph{#1}}
% \DeclareFieldFormat[article]{title}{\mkbibquote{#1}}
% \DeclareFieldFormat[article]{citetitle}{\mkbibquote{#1}}
% \DeclareFieldFormat[inreference]{citetitle}{\mkbibquote{#1}}
% \DeclareFieldFormat{journaltitle}{\mkbibemph{#1}}
% \DeclareFieldFormat{citejournaltitle}{\mkbibemph{#1}}

\usepackage[style=ext-verbose-inote]{biblatex}

% \DefineBibliographyExtras{french}{%
%   \renewcommand{\mkbibnamefamily}[1]{#1}%
% }

\addbibresource{../bibliography.bib}

% Automatically cite authors in full at first, then only by last
% name. See https://tex.stackexchange.com/a/314708
\makeatletter
\newrobustcmd*{\cbx@nametracker@global}[1]{%
  \xifinlistcs{#1}{cbx@bseen@names@\the\c@refsection}
    {}
    {\listcsxadd{cbx@bseen@names@\the\c@refsection}{#1}}}

\newrobustcmd*{\cbx@nametracker@context}[1]{%
  \iftoggle{blx@footnote}
    {\xifinlistcs{#1}{cbx@fseen@names@\the\c@refsection}
       {}
       {\listcsxadd{cbx@fseen@names@\the\c@refsection}{#1}}}
    {\xifinlistcs{#1}{cbx@bseen@names@\the\c@refsection}
       {}
       {\listcsxadd{cbx@bseen@names@\the\c@refsection}{#1}}}}

\newrobustcmd*{\cbx@ifnameseen@global}[1]{%
  \xifinlistcs{#1}{cbx@bseen@names@\the\c@refsection}}

\newrobustcmd*{\cbx@ifnameseen@context}[1]{%
  \iftoggle{blx@footnote}%
    {\xifinlistcs{#1}{cbx@fseen@names@\the\c@refsection}}%
    {\xifinlistcs{#1}{cbx@bseen@names@\the\c@refsection}}}

\DeclareBibliographyOption[string]{nametracker}[true]{%
  \ifcsdef{blx@opt@nametracker@#1}
    {\csuse{blx@opt@nametracker@#1}}
    {\blx@err@invopt{nametracker=#1}{}}}

\def\blx@opt@nametracker@global{%
  \let\cbx@ifnameseen\cbx@ifnameseen@global
  \let\cbx@nametracker\cbx@nametracker@global}

\let\blx@opt@nametracker@true\blx@opt@nametracker@global

\def\blx@opt@nametracker@false{%
  \protected\long\def\cbx@ifnameseen##1##2##3{##3}%
  \let\cbx@nametracker\relax}

\def\blx@opt@nametracker@context{%
  \let\cbx@ifnameseen\cbx@ifnameseen@context
  \let\cbx@nametracker\cbx@nametracker@context}

\appto\blx@secinit{%
  \ifcsundef{cbx@bseen@names@\the\c@refsection}
    {\global\cslet{cbx@bseen@names@\the\c@refsection}\@empty}
    {}%
  \ifcsundef{cbx@fseen@names@\the\c@refsection}
    {\global\cslet{cbx@fseen@names@\the\c@refsection}\@empty}
    {}}

\InitializeCitationStyle{%
  \global\cslet{cbx@bseen@names@\the\c@refsection}\@empty
  \global\cslet{cbx@fseen@names@\the\c@refsection}\@empty}

\ExecuteBibliographyOptions{nametracker=context}

\DeclareNameFormat{labelname}{%
  \cbx@ifnameseen{\thefield{hash}}
    {\ifcase\value{uniquename}%
       \usebibmacro{name:family}
         {\namepartfamily}
         {\namepartgiven}
         {\namepartprefix}
         {\namepartsuffix}%
     \or
       \ifuseprefix
         {\usebibmacro{name:given-family}
           {\namepartfamily}
           {\namepartgiveni}
           {\namepartprefix}
           {\namepartsuffixi}}
         {\usebibmacro{name:given-family}
           {\namepartfamily}
           {\namepartgiveni}
           {\namepartprefixi}
           {\namepartsuffixi}}%
     \or
       \usebibmacro{name:given-family}
         {\namepartfamily}
         {\namepartgiven}
         {\namepartprefix}
         {\namepartsuffix}%
     \fi}
    {\usebibmacro{name:given-family}
       {\namepartfamily}
       {\namepartgiven}
       {\namepartprefix}
       {\namepartsuffix}%
     \cbx@nametracker{\thefield{hash}}}
    \usebibmacro{name:andothers}}
\makeatother