diff --git a/misc/translator/tmpl_process3.pl b/misc/translator/tmpl_process3.pl
index 2d463d2412..41ed676261 100755
--- a/misc/translator/tmpl_process3.pl
+++ b/misc/translator/tmpl_process3.pl
@@ -64,6 +64,8 @@ sub text_replace_tag {
     my $translated_p = 0;
     for my $a ( 'alt', 'content', 'title', 'value', 'label', 'placeholder', 'aria-label' ) {
         if ( $attr->{$a} ) {
+
+            # xt/tt_valid.t must be adjusted if the following conditions are modified
             next if $a eq 'label'   && $tag ne 'optgroup';
             next if $a eq 'content' && $tag ne 'meta';
             next
@@ -140,7 +142,7 @@ sub text_replace {
                     $kind == C4::TmplTokenType::TAG && %$attr ? text_replace_tag( $t, $attr ) : $t;
                 }
             );
-        } elsif ( $kind eq C4::TmplTokenType::TAG && %$attr ) {
+        } elsif ( $kind eq C4::TmplTokenType::TAG && $attr && %$attr ) {
             print $output text_replace_tag( $t, $attr );
         } elsif ( $s->has_js_data ) {
             for my $t ( @{ $s->js_data } ) {
@@ -158,6 +160,8 @@ sub text_replace {
             # Quick fix to bug 4472
             $t = "<!DOCTYPE stylesheet [" if $t =~ /DOCTYPE stylesheet/;
             print $output $t;
+        } elsif ( !$attr ) {
+            warn "Error: file contains incorrect TT structures";
         }
     }
 }
diff --git a/t/db_dependent/misc/translator/tt/en/sample-not-working-2.tt b/t/db_dependent/misc/translator/tt/en/sample-not-working-2.tt
new file mode 100644
index 0000000000..96485fa99e
--- /dev/null
+++ b/t/db_dependent/misc/translator/tt/en/sample-not-working-2.tt
@@ -0,0 +1,3 @@
+<p>The following line will be translated but broken:</p>
+<span [% IF required %]required="required"[% END %] title="Don't use TT directives if another attribute is translatable"></span>
+<p>Will be translated</p>
diff --git a/t/db_dependent/misc/translator/sample-not-working.tt b/t/db_dependent/misc/translator/tt/en/sample-not-working.tt
similarity index 100%
rename from t/db_dependent/misc/translator/sample-not-working.tt
rename to t/db_dependent/misc/translator/tt/en/sample-not-working.tt
diff --git a/t/db_dependent/misc/translator/sample.tt b/t/db_dependent/misc/translator/tt/en/sample.tt
similarity index 100%
rename from t/db_dependent/misc/translator/sample.tt
rename to t/db_dependent/misc/translator/tt/en/sample.tt
diff --git a/t/db_dependent/misc/translator/xgettext.pl.t b/t/db_dependent/misc/translator/xgettext.pl.t
index 622c71dc53..9cb2aa63cf 100755
--- a/t/db_dependent/misc/translator/xgettext.pl.t
+++ b/t/db_dependent/misc/translator/xgettext.pl.t
@@ -2,16 +2,16 @@
 
 use Modern::Perl;
 
-use File::Slurp;
-use File::Temp qw(tempdir);
-use FindBin    qw($Bin);
+use File::Slurp qw(read_file write_file);
+use File::Temp  qw(tempdir);
+use FindBin     qw($Bin);
 use Locale::PO;
-use Test::More tests => 21;
+use Test::More tests => 25;
 use Test::NoWarnings;
 
 my $tempdir = tempdir( CLEANUP => 1 );
 
-write_file( "$tempdir/files", "$Bin/sample.tt" );
+write_file( "$tempdir/files", "$Bin/tt/en/sample.tt" );
 
 my $xgettext_cmd = "$Bin/../../../../misc/translator/xgettext.pl -o $tempdir/Koha.pot -f $tempdir/files";
 
@@ -56,10 +56,36 @@ for ( my $i = 0 ; $i < @expected ; $i++ ) {
 
 is( scalar @$pot, 1 + scalar(@expected) );
 
-write_file( "$tempdir/files", "$Bin/sample-not-working.tt" );
+write_file( "$tempdir/files", "$Bin/tt/en/sample-not-working.tt" );
 
 $xgettext_cmd = "$Bin/../../../../misc/translator/xgettext.pl -o $tempdir/Koha.pot -f $tempdir/files 2>/dev/null";
 
 system($xgettext_cmd);
 $pot = Locale::PO->load_file_asarray("$tempdir/Koha.pot");
 is( scalar @$pot, 0, 'xgettext.pl failed to generate a POT file because of incorrect structure' );
+
+write_file( "$tempdir/files", "$Bin/tt/en/sample-not-working-2.tt" );
+
+$xgettext_cmd = "$Bin/../../../../misc/translator/xgettext.pl -o $tempdir/Koha.pot -f $tempdir/files 2>/dev/null";
+
+system($xgettext_cmd);
+$pot = Locale::PO->load_file_asarray("$tempdir/Koha.pot");
+is( scalar @$pot, 4, 'xgettext.pl generated a POT file' );
+
+my $pot_content = read_file("$tempdir/Koha.pot");
+$pot_content =~
+    s|msgid "Don't use TT directives if another attribute is translatable"\nmsgstr ""|msgid "Don't use TT directives if another attribute is translatable"\nmsgstr "Ne pas utiliser TT si un autre attribut est traduisible"|gms;
+$pot_content =~ s|msgid "Will be translated"\nmsgstr ""|msgid "Will be translated"\nmsgstr "Ceci sera traduit"|gms;
+write_file( "$tempdir/Koha.pot", $pot_content );
+
+my $tempdir_fr = tempdir( CLEANUP => 1 );
+my $install_cmd =
+    "$Bin/../../../../misc/translator/tmpl_process3.pl -q install -i $Bin -o $tempdir_fr  -s $tempdir/Koha.pot -r -n marc21 -n unimarc";
+system($install_cmd);
+
+my $content = read_file("$tempdir_fr/tt/en/sample-not-working-2.tt");
+like( $content, qr{Ne pas utiliser TT si un autre attribut est traduisible} );
+like( $content, qr{Ceci sera traduit} );
+
+# So far so good, but #FIXME:
+like( $content, qr{<span %\]="%\]" %\]required="required" \[%="\[%"} );
diff --git a/xt/author/tt_valid.t b/xt/author/tt_valid.t
new file mode 100644
index 0000000000..f343316996
--- /dev/null
+++ b/xt/author/tt_valid.t
@@ -0,0 +1,115 @@
+#!/usr/bin/perl
+
+# This file is part of Koha.
+#
+# Koha is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# Koha is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Koha; if not, see <http://www.gnu.org/licenses>.
+
+use Modern::Perl;
+use Test::NoWarnings;
+use Test::More;
+use C4::TTParser;
+use Array::Utils qw( array_minus );
+
+use Koha::Devel::Files;
+my $dev_files  = Koha::Devel::Files->new( { context => 'tidy' } );
+my @tt_files   = $dev_files->ls_tt_files;
+my @exclusions = qw(
+    t/db_dependent/misc/translator/tt/en/sample-not-working.tt
+    t/db_dependent/misc/translator/tt/en/sample-not-working-2.tt
+    t/db_dependent/misc/translator/tt/en/sample.tt
+);
+@tt_files = array_minus @tt_files, @exclusions;
+
+plan tests => scalar(@tt_files) + 1;
+
+my @translatable_attributes = qw(alt content title value label placeholder aria-label);
+
+my $checkers = [
+    {
+        description => 'TT syntax: incorrectly uses of TT tags in HTML tags',
+        check       => sub {
+            my ( $self, $name, $token ) = @_;
+            my $attr = $token->{_attr};
+            next unless $attr;
+            my @errors;
+            if ( $attr->{'[%'} or $attr->{'[%-'} ) {
+                for my $attribute (@translatable_attributes) {
+
+                    # The following tests come from tmpl_process3.pl sub text_replace_tag
+                    next if $attribute eq 'label'   && $token->{_string} !~ /^<optgroup/;
+                    next if $attribute eq 'content' && $token->{_string} !~ /^meta/;
+                    next
+                        if $attribute eq 'value'
+                        && ( $token->{_string} !~ /^input/ );    # || additional check on checkbox|hidden|radio needed?
+                    if ( exists $attr->{$attribute} ) {
+                        if ( $attr->{$attribute}->[2] =~ m{$attribute=[^[]} ) {
+                            push @errors, $token->{_lc};
+                        }
+                    } elsif ( exists $attr->{"%]$attribute"} ) {
+                        push @errors, $token->{_lc};
+                    }
+                }
+            }
+            return @errors;
+        },
+    },
+    {
+        description => '<body> tag with id and class attributes',
+        check       => sub {
+            my ( $self, $name, $token ) = @_;
+            return if $name =~ /bodytag\.inc/;
+            my $tag = $token->{_string};
+            return ( $tag =~ /^<body/ && ( $tag !~ /id=".+"/ || $tag !~ /class=".+"/ ) )
+                ? ( $token->{_lc} )
+                : ();
+        },
+    },
+];
+
+for my $filepath (@tt_files) {
+    my $parser = C4::TTParser->new;
+    $parser->build_tokens($filepath);
+    my @errors;
+    while ( my $token = $parser->next_token ) {
+        my $attr = $token->{_attr};
+        next unless $attr;
+
+        for my $checker (@$checkers) {
+            my @e = $checker->{check}->( $checker, $filepath, $token );
+            push @errors, @e if @e;
+        }
+    }
+    is( scalar(@errors), 0 ) or diag( "$filepath: " . join( ', ', @errors ) );
+}
+
+=head1 NAME
+
+xt/author/tt_valid.t
+
+=head1 DESCRIPTION
+
+This test validates .tt files.
+
+For the time being, two validations are done:
+
+[1] Test if TT files contain TT directive within HTML tag. For example:
+
+  <li[% IF
+
+This kind of construction MUST be avoided because it breaks Koha translation
+process.
+
+[2] Test tag <body> tags have both attibutes 'id' and 'class'
+
+=cut